Pacific Dualies Pressure Plus TPMS is a fully programmable and expandable system for up to 34 wheels. This system measures temp. and pressure per wheel / axle. PSI and temp. alarm code settings can be customized per axle. System is easy to work with and install, and works with any type of vehicle. This TPMS uses light weight, valve stem sensors that screw on top of the tire valve stems. These are easy to install, and have removable caps for easy battery replacement. System runs on 6 AA batteries, and can also be hard wired so battery power is not needed.