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Mass-Flux Twin

Feelfit body composition fused with wrist physiology

Feelfit scale link

offline

Step on the scale, then tap Pair. The link is remembered and re-arms itself automatically.

If no data arrives
  1. 1. Wake the platform. Step on the scale so its display lights up — the radio only advertises while the load cells are active.
  2. 2. Force-close the vendor app. If the official scale app is running it holds the Bluetooth link. Swipe it away, then tap Re-pair.
  3. 3. Stay within a metre of the platform while the mass settles, and keep the screen on until the capture line appears.

MANUAL / FEELFIT APP ENTRY

If the browser has no Bluetooth access, read the two numbers off the Feelfit app and type them here. Impedance is optional — without it the engine falls back to anthropometric estimation and says so.

Anthropometry

Height, age and sex are non-negotiable inputs to the Kyle and Kushner equations — the resistance index is H²/R. Getting height wrong by 2 cm moves fat-free mass by roughly 0.6 kg.

No scale reading yet. Pair the Feelfit scale or log one manually above — the fusion engine needs a mass and, ideally, an impedance value before it can index your wrist physiology to real tissue.

Match the scale exactly

auto

Paste one raw packet from your scale and the weight its own screen showed. The app works out how that scale encodes weight and locks it in, so this console and the scale always agree.

What this does that nothing else does

  • Wrist signals indexed to measured lean mass. Watches index to body mass or to nothing. Cardiac output tracks fat-free mass, so every heart-rate-derived number here is divided by tissue the scale actually measured.
  • Impedance re-derived, never inherited. The scale's proprietary percentages are discarded; mass and ohms go into published equations so the maths is auditable and consistent across devices.
  • Fluid-shift correction on the wearable. A TBW/FFM ratio above the 73.2% constant flags extracellular expansion, so a "bad HRV day" is separated from a water-loading artefact — the same distinction NASA's unloading work depends on.
  • Partition-aware advice. Weight loss is judged by whether lean or fat mass is falling faster, then cross-read against the watch's autonomic and energy channels.