Aftermarket Wheels & Service Tire Pressure Monitor - SVC TPM

[NM H3]

The valve stem cap is just a cap, nothing else in relation to the TPM. The sensor is inside of the tire, connected to the metal valve stem. The metal valve stem serves as the antenna for the sensor.
I bought my new wheels from Discount Tire, and they took the sensors out of my old wheels, and put them into the new ones. They also put standard stems back onto my old wheels without any additional charge.