These Extra Brass Transmitters are compatible with all TireMinder Tire Pressure Monitoring Systems. Includes 2 CR1632 replaceable batteries (with a 9 to 14 month lifespan). For use with rubber, brass, chrome, nickel, or steel valve stems. Two locking nuts included Two CR1632 replaceable batteries included For use with rubber/brass/chrome/nickel/steel valve stems | TireMinder Extra Brass Transmitters for Tire Pressure Monitoring Systems, 2-Pack