Replaces the original sensors on Jeep Wrangler where the batteries are dead (age). I managed to buy 4 sensors for the price the local car dealer was asking for one. The local tire shop installed the sensors in 30 minutes and they were pre-programmed so the tire sensor light went out in less than 1 mile. Excellent quality - managed to replace 5 sensors and install them for less than the dealer wanted to charge for a tyre. It has been working for several months, there were no problems with the sensors. Will do the same on other vehicles when the sensor batteries are dead