Schrader now offers both a battery powered #20256 and hardwired #20257 version of their stand alone TPMS retrofit kits. These kits make it easy to setup a tire pressure monitoring system on a vehicle that did not come with one from the factory. These kits are also very popular for motorsport fans in racing and off road. MSRP is about $269. so it is very reasonable for such a quality kit.

Hardwired kit:


Battery operated kit: