What a wearer feels is not weight. Under 200 grams per band and about 700 to 900 grams on the body without the phone, likely lower: parts under 100 grams, the battery about 100, the rest bands, pods, cables, and the mount. Nobody feels that weight; they feel heat, sweat, chafe, and strap migration. A rest after about two hours of continuous wear and a full waking day as the daily limit, until measured on real wearers. At a running pace of 3 meters per second, 70 milliseconds is 21 centimeters of travel, while the 15 Hz ground grid sees a step edge only every 20 centimeters, which is tight; running is not claimed until the test plan requires and verify it. Source: docs/12.
Weight: under 200 g per band; total on body electronics and bands, excluding the phone, about 700 to 900 g, and likely lower. Parts alone are under 100 g; the battery is about 100 g; bands, pods, cables, and mount make up the rest. Nobody feels the weight. They feel heat, sweat, chafe, and strap migration, which is where the engineering effort goes.
Wear time: a rest after about two hours of continuous wear, and a daily limit of a full waking day, as starting standards until measured on real wearers. Vibration is intermittent and low amplitude, far below hand arm vibration injury thresholds.
Age: adults first. Children need resized bands and reduced amplitude. Older adults lose vibrotactile sensitivity with age, so a per wearer amplitude calibration step is planned.
Running, about 3 m per second: 70 ms is 21 cm of travel, which is acceptable, but a 15 Hz ground grid sees a step edge only every 20 cm, which is tight. Closures must be snugger against migration. IMU gait detection switches a running mode: scene description pauses, the ground grid priority rises, and only the reflex belt runs. Running is not claimed until the test plan requires and verify it.
Source: docs/12-human-limits.md, the engineering record. Every number on this page is read from that file. If a fact is not in the record, it is measured on the bench, or it stays off this site.