Armfit Deep Zero

The entry point into 24/7 tracking — and it never asks you for another pound.

The most affordable way into the screenless tracker category. It won't match WHOOP's sensor depth, and it isn't trying to. What it does is keep a continuous record of your heart, your sleep and your oxygen without a subscription, ever.

What it tracks, 24/7

• Heart rate
• Blood oxygen
• Sleep
• Daily activity, steps and calories

What makes it different

• Zero membership fee for life — no renewals, no locked features, no hidden costs
• A full week of battery — charge it once a week and forget about it
• Barely-there weight — light enough to forget about at the gym, at your desk, and in bed
• Clear app insights — readable charts and progress tracking instead of a wall of raw numbers

Specs

• Battery: up to 7 days per charge
• Water: water-resistant, built for daily wear and workouts
• Wear: wrist or upper arm, adjustable nylon band
• Subscription: none, permanently
• Works with iPhone and Android

Best for: a first tracker, a gift, or anyone curious about sleep and recovery data who isn't ready to spend five figures to find out.