USB Seatbelt Therapy Heater

I have the concept sketched and a clear use-case in mind: a slim, portable heating attachment that slips under a car’s torso belt, delivers therapeutic warmth through three selectable temperature settings, and recharges via USB without ever impeding the restraint’s normal function... (Budget: £250 - £750 GBP, Jobs: CAD/CAM, Electrical Engineering, Electronics, Materials Engineering, Mechanical Engineering, Product Design, Prototyping, Thermal Analysis)