Biometric Mastery. Zero Screen.
Introducing CYOK Band and CYOK Ring—screenless luxury wearables engineered for locked morning readiness, 4-stage sleep architecture, logarithmic 0–21 Day Strain, strength tonnage, and overnight vitals. No subscription.
CYOK Band · CYOK Ring
Perforated Sport Strap · 0–21 Strain
PVD Stainless Steel · Sleep & HRV
Up to 7 days CYOK Ring standby (1.5h case charge) · Up to 20 days CYOK Band battery.
Explore CYOK Band & CYOK Ring.
Engineered without distracting screens and with no subscription. Sign up to be notified as soon as they arrive.
CYOK Band
Screenless Precision Engineered for High-Output Days & Recovery.
A distraction-free, screenless biometric strap built for logarithmic Day Strain (0–21), Muscular Load tonnage tracking, continuous autonomic stress monitoring, and deep overnight recovery.
No subscription
CYOK Ring
Precision Stainless Steel Recovery & Sleep Architecture on Your Finger.
Precision-crafted surgical-grade stainless steel smart ring with recessed palmar optical sensors for nocturnal HRV, 4-stage sleep hypnograms, Recovery Index, and up to 7-day battery life with wireless charging case.
Why Screenless? Silence, Deep Sleep & Massive Autonomy.
Traditional smartwatches bombard you with notification anxiety and die after 24 hours. CYOK eliminated the screen to give you clinical-grade biometric data, up to 20 days of battery life, and zero visual distractions.
Deeper Sleep & Melatonin
Zero screens accidentally flashing awake in your dark bedroom. Zero blue light before bed suppressing melatonin and degrading your Deep & REM restorative sleep stages.
Up to 20 Days Autonomy
Displays eat over 75% of a smartwatch battery. By removing the screen, CYOK Band delivers up to 20 days per charge, and CYOK Ring up to 7 days (with pocket wireless case).
Zero Notification Anxiety
No buzzes for spam emails, no chat previews, no endless dopamine pings. Your wearable silently records clinical metrics; you review actionable insights in the app on your own schedule.
Horological Freedom
Wear your heirloom mechanical chronograph (Rolex, Omega, Cartier, Seiko) or fine jewelry freely without looking redundant wearing two glowing black rectangles.
Apple HealthKit · Zero Monthly Subscription
Every single metric explained. Uncut on your iPhone.
CYOK hardware quietly captures your pulse-wave telemetry 24/7 with zero screens, while the native iOS app translates it into 8 clinical intelligence pillars. Explore every screen presented in its entirety inside an authentic iPhone mockup.
Know Exactly When to Push and When to Rest.
Calculated every morning from your nocturnal RMSSD HRV nadir, resting heart rate, and sleep quality.
The CYOK app wakes with you, delivering a calibrated 0–100% Readiness score before your feet touch the floor. By analyzing nocturnal autonomic nervous system balance without screen disturbance, CYOK identifies whether your body is primed for high physical strain or needs active restoration.
Unlike generic fitness trackers that rely on simple pulse readings, CYOK captures continuous photoplethysmography (PPG) at 50Hz all night long through the Band or Ring. The algorithms establish your personal 14-day rolling physiological baseline, filtering out transient spikes so your score reflects genuine biological capacity.
Readiness >80% signals a green light for progressive overload. Readiness <50% advises light mobility and an earlier bedtime.
Screenless hardware means 0 glowing screens in bed, 0 blue light exposure, and up to 20 days of uninterrupted telemetry.
Click any screen below to inspect its features
All 8 native iOS 18+ screens inside iPhone 16 Pro Max mockups. Zero monthly paywalls.
Clinical-Grade Biometric Intelligence. No Subscription.
Both CYOK Band and CYOK Ring include full access in the native CYOK companion app to all 9 physiological intelligence pillars—from locked morning readiness and 4-stage sleep hypnograms to mechanical strength tonnage, Symptom Radar, and luteal hormone compensation.
Morning Readiness & Recovery Intelligence
A locked, manipulation-free morning score calibrated against your 14-day personal baseline—with zero anxiety.
HRV 74 ms (+9 ms vs 14d baseline) · RHR 49 bpm · Limiting Factor: None
Conservative Daily Recovery Score (0–100%)
Locked at WakeCombines nocturnal HRV (RMSSD), Resting Heart Rate, Sleep Performance, Respiratory Rate, SpO2, and recent 36-hour Strain into a locked morning readiness score that never inflates from daytime wrist movement.
4-Pillar Recovery Driver Breakdown
14-Day Personal BaselineVisualizes Sleep, HRV, Resting Pulse, and Stress Balance against your 14-day personal baseline and automatically identifies your #1 limiting factor each morning.
1-Tap Rest Mode & Mindful Trend Mode
Optimal · Steady · RestorativeDesigned around real human physiology and mental peace—whether you are recovering from illness or stepping away from daily percentages.
- Rest Mode: Pauses daily Strain and step goals during illness, injury, or jet lag so recovery is prioritized without breaking streaks.
- Mindful Trend Mode: Hides anxiety-inducing raw morning percentages (%) and replaces them with calm qualitative states (Optimal · Steady · Restorative) while preserving 14–30 day trends.
Shareable Social Story Cards
1-Tap Story Export1-tap dark-mode summary card for sharing your daily Readiness, Sleep, HRV, and RHR with your coach or training community.
All 9 CYOK Biometric Intelligence Pillars
Select any pillar to explore its interactive telemetry. Included with no subscription.
Morning Readiness & Recovery Intelligence
A locked, manipulation-free morning score calibrated against your 14-day personal baseline—with zero anxiety.
- •Conservative Daily Recovery Score (0–100%)
Combines nocturnal HRV (RMSSD), Resting Heart Rate, Sleep Performance, Respiratory Rate, SpO2, and recent 36-hour Strain into a locked morning readiness score that never inflates from daytime wrist movement.
- •4-Pillar Recovery Driver Breakdown
Visualizes Sleep, HRV, Resting Pulse, and Stress Balance against your 14-day personal baseline and automatically identifies your #1 limiting factor each morning.
- •1-Tap Rest Mode & Mindful Trend Mode
Designed around real human physiology and mental peace—whether you are recovering from illness or stepping away from daily percentages.
- •Shareable Social Story Cards
1-tap dark-mode summary card for sharing your daily Readiness, Sleep, HRV, and RHR with your coach or training community.
Sleep Architecture, Recovery Index & Smart Alarm
4-stage sleep hypnograms, nocturnal heart-rate stabilization curves, dynamic sleep debt planning, and gentle haptic wake.
- •4-Stage Sleep Hypnogram & Architecture
Tracks Awake, REM, Light (Core), and Deep (Slow-Wave) sleep stages alongside sleep efficiency, sleep latency, and restorative sleep percentage.
- •Overnight HR Stabilization Curve & Recovery Index
Analyzes the geometry of your nocturnal cardiovascular curve to reveal how late meals, stress, or optimal recovery shaped your night.
- •Dynamic Sleep Coach & Sleep Debt Planner
Calculates tonight's exact sleep need by combining your baseline need + today's Day Strain + accumulated Sleep Debt, minus restorative daytime naps.
- •Automatic Daytime Nap Detection
Automatically classifies 20–180 minute daytime sleep sessions as naps and credits them toward reducing your active sleep debt.
- •Haptic Smart Wake Alarm
Wakes you via gentle wrist or finger vibration during your lightest sleep stage inside a configurable 15–30 minute window before your final alarm.
Day Strain (0–21), Strength Trainer & GPS Workouts
Cardiovascular zone load meets mechanical weightlifting tonnage so low-HR heavy sessions are never under-reported.
- •Logarithmic Day Strain (0.0–21.0) & Target Strain Corridor
Translates all-day heart-rate zone time (Zones 1–5) and passive movement into a 0–21 exertion score matched to an optimal daily Strain target derived from your morning Recovery.
- •Strength Trainer & Muscular Load Engine
Logs resistance exercises, sets, reps, weight (kg), and RPE (1–10) to compute daily mechanical tonnage and Muscular Strain—solving the problem of low-HR weightlifting under-reporting exertion.
- •Live GPS & Multi-Sport Workout Tracker
Supports Running, Walking, Cycling, Strength Training, HIIT, Yoga/Mobility, and Swimming with real-time HR zones, pace, GPS route mapping, and Dynamic Island / Lock Screen Live Activities.
- •Automatic Workout Detection
Passively detects sustained walking, running, cycling, HIIT, and strength bursts from cadence, accelerometer intensity, and HR elevation.
Overnight Vitals & Symptom Radar
Multi-parameter biometric deviation tracking that catches physiological strain 24–48 hours before you feel run down.
- •5-Pillar Overnight Vitals Corridor
Tracks Resting Heart Rate, Heart Rate Variability (HRV), Respiratory Rate, Wrist/Skin Temperature Delta (±°C), and Blood Oxygen (SpO2) against your 30-day personal corridor, with a 7-night outlier timeline.
- •Symptom Radar (Early Illness & Biometric Strain Detection)
Evaluates simultaneous overnight shifts across Skin Temperature, Respiratory Rate, RHR, and HRV to flag No Signs of Strain, Minor Biometric Strain, or Major Biometric Strain up to 24–48 hours before symptoms appear, with a 1-tap Rest Mode trigger.
Stress Monitor, Autonomic Biofeedback & Longevity
Real-time daytime autonomic arousal separation, live HRV-guided breathwork, and biological cardiovascular aging velocity.
- •Continuous Daytime Stress & 4-State Autonomic Distribution
Distinguishes non-movement HR/HRV autonomic arousal from physical exercise and breaks your day into 4 states: Restored, Relaxed, Engaged, and Stressed.
- •Interactive Live Biofeedback Breathwork
Built-in guided Physiological Sigh (double inhale + extended exhale) and Coherent 5.5s Breathing coach with real-time wearable HR & HRV delta feedback.
- •Cardiovascular Health Age, Pace of Aging & VO2 Max
Estimates your biological Health Age vs. chronological age, Pace of Aging multiplier, 14-Day Acute-to-Chronic Workload Ratio (ACWR), and Circadian Social Jetlag.
Lifestyle Journal, Habit Correlation & Self-Experimentation
Turn your body into a clinical N=1 lab—discovering exactly which habits boost or sabotage your HRV and deep sleep.
- •1-Tap Daily Behavior & Context Journal
Logs 25+ habits (Alcohol, Late Meal, Caffeine Cutoff, Magnesium, Sauna, Cold Plunge, Blue-Light Glasses, Breathwork, Creatine, Zone 2, Screen in Bed, etc.) plus subjective Mood, Energy, Soreness, and Stress.
- •Statistical Habit Impact Engine & Habit History Explorer
Calculates how each habit shifts your next-morning Recovery (%), HRV (ms), and Resting HR (bpm) on 'Yes' vs. 'No' nights, with a tap-through Habit History Explorer showing every logged date.
- •Guided 14-Day Lifestyle Experiments
Structured N=1 protocols (Magnesium Before Bed, No Alcohol Reset, 6+ Hours Early Caffeine Cutoff, No Late Meals, Daily Breathwork) with progress rings and baseline vs. experiment biometric deltas.
Cycle & Hormone Phase Intelligence
Physiology-aware scoring that respects natural luteal thermal and heart-rate shifts instead of penalizing your recovery.
- •4-Phase Cycle Tracking & Thermal Shift Guidance
Tracks Follicular, Ovulatory, Luteal, and Menstrual phases with training and recovery guidance tailored to hormone shifts.
- •Luteal Baseline Compensation
Automatically compensates for natural progesterone-driven +0.35°C skin temperature and +3 bpm RHR rises during the Luteal phase so luteal nights aren't unfairly penalized as poor recovery.
Precision Hardware Hub, Calibration & Low-EMF Mode
Dedicated optical calibration for wrist, bicep, or finger placement, Quiet Low-EMF sync control, and safe OTA firmware updates.
- •Wear Placement Profile Calibration
Dedicated sensor calibration for Wrist, Bicep Band, and Ring / Finger placement to optimize step-rejection and optical PPG pulse-wave filtering.
- •Quiet / Low-EMF Sync Mode
Pauses continuous background BLE polling and syncs only on manual pull-to-refresh or when placed on the charger.
- •Seamless CYOK Band & CYOK Ring Support
Full hardware management in the CYOK app with automatic profile recognition and unified biometric history.
- •In-App OTA Firmware Update (DFU) Utility
Pre-flight BLE link check, ≥ 30% battery safety gate, and cryptographic firmware status verification.
Ecosystem, Widgets, Localization & Data Ownership
Your biometrics belong to you—with on-device Physician PDF reports, iOS 18 Control Center widgets, and full English & Romanian support.
- •Home Screen, Lock Screen & Control Center Widgets
Includes CYOK Daily Summary, Overnight Vitals, Day Summary, Workout Launcher, Workout Live Activity, and iOS 18 Control Center controls.
- •Apple Health Two-Way Sync & Calendar Stress Insights
Syncs workouts, sleep, HR, HRV, SpO2, and steps with Apple HealthKit, and correlates busy calendar days with physiological daytime stress.
- •Complete Data Ownership (PDF, JSON & CSV Exports)
Local on-device generation of a 30-Day Physician PDF Report, a complete JSON Archive, and a spreadsheet-ready Daily Vitals CSV.
- •Full Bilingual Localization (English & Romanian)
1,457+ localized strings natively crafted across English and Romanian.
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