Luffu Link costs $249.99, and the Luffu Family Plan it needs runs $19.99 a month or $199.99 a year for up to four people, cellular data included. Shipping starts in the US in early 2027. Neither number existed on Tuesday, when the screenless band arrived with no price and no ship date, and neither did the third missing piece: the band tracks steps, activity, sleep, heart rate and HRV, runs up to five days on a charge, is water resistant to 50 metres, and has GPS, Bluetooth and 4G LTE-M inside.

Gadgets & Wearables reported the first year at roughly $450 once the band and the annual plan are counted together, which makes this a different purchase from a fitness tracker you buy once. The subscription is also what pays for the cellular link, so the band stays online with no phone nearby and can share the wearer's location with selected family members. A button on the band records a quick voice note about taking medication or feeling unwell, and that note lands in the Luffu app next to the health readings. A double press sends a check-in to the family. The button does not call 911.