La Crosse Technology TX37U-IT 915MHz Wireless Temperature Sensor Remote wireless temperature sensor for use with a wide range of La Crosse Technology weather systems Equipped for wall mount; transmits data at 915 MHz frequency up to 330 feet unobstructed to base unit Assesses outdoor temperatures from 31.9 to +139 degrees F; also can monitor indoor temperatures Requires separate purchase of a compatible base and 2 AA batteries; install out of direct rain or sun Measures 1-1/2 inches wide by 4/5 inches deep by 5 inches high; limited 1-year warranty, kindly refer the user manual given below for troubleshooting steps.