Spare part for wrist bend for old Misfit Shine 1 generation:
https://www.walmart.com/ip/Misfit-Wearables-Shine-Activity-and-Sleep-Monitor/40519636

You can buy wrist band here:
https://www.amazon.co.uk/hellosy-Replacement-Wristband-Wireless-Activity/dp/B01CVQNH9Q/
or
https://www.amazon.co.uk/KAIFANG-Wrist-Misfit-Bracelet-WristBand-Red/dp/B0751B8G57/
and than insert device and secure it with 3D printed part from me.