HIIT Interval Timer | Cero vs K2 (a514e2)

Build an interval workout around the way you train. Cero is a flexible interval timer for HIIT, Tabata, circuit training, WODs and HYROX preparation. Set up a quick work/rest timer or program each interval in detail. Distinct colors, large controls and reliable cues keep you focused on the session instead of the clock. BUILD YOUR SESSION • Set work, recovery, sets, warm-up and cool-down. • Create advanced workouts with custom intervals, colors, icons and intensity levels. • Save, duplicate and reorder timers. • Share timers by file or QR code. • Review completed sessions in workout history. STAY IN THE WORKOUT • Follow compatible sessions with Live Activities and Dynamic Island. • Start saved or recent timers from Home Screen widgets. • Use Siri and Shortcuts to start, pause, resume and stop a timer. • Put Gym Display on a larger screen or mirrored TV. • Choose a default song or assign music to individual intervals. • Customize sounds, voice cues, vibrations and background alerts. TRAIN BY HEART RATE Adaptive HR can extend recovery until you reach your target heart rate, then guide hard efforts with low and high alerts. Pair a Bluetooth heart-rate monitor with iPhone or train with heart-rate data from Apple Watch. COUNTDOWN AND STOPWATCH The built-in countdown and lap stopwatch cover warm-ups, station changes, rest periods and race-day practice. Stopwatch sessions continue after you close and reopen the app. ON APPLE WATCH Run saved workouts from your wrist, follow heart rate and use the standalone countdown and stopwatch. Cero can save completed workouts and estimated calories to Apple Health. Automatic iCloud backups help protect saved timers and custom intervals. Useful for HIIT, Tabata, circuits, EMOM-style workouts, boxing rounds, strength and conditioning, indoor cycling, running intervals and hybrid race preparation. Feedback and suggestions: hi@flawless.studio Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

K2 is the app you use to follow the plan your personal trainer built for you. It's not a catalog of generic routines: what's inside was written by a real person, for you. YOUR DAY, AT A GLANCE What's due today: your meals, your workout and your habits, all on one screen. YOUR WORKOUT, AS YOU GO Sets with their weight and reps, rest with a timer, and what you did last time right next to it so you know if you're improving. Mark each set based on how it went. If you hit a new record, it tells you. And the rest countdown shows on the lock screen, no need to unlock your phone. YOUR DIET, NO CALCULATOR NEEDED Your meals with quantities already worked out, the day's macros counted for you, and swaps for when you don't have what's listed. Mark what you eat and your trainer sees it. YOUR PROGRESS Log your weight whenever you like and save your progress photos. The weekly check-in captures measurements, how you're feeling and adherence, and your trainer reads it to adjust your plan. TALK TO YOUR TRAINER Messages inside the app, plus notes on any meal or exercise. WORKS WITHOUT SIGNAL Your plan is saved on your phone. It works out even in the basement gym. K2 requires a trainer to set up your account: there is no open sign-up.