Digi-Code’s Open\Close\Stop commercial door operator radio control system operates at a 433MHz radio frequency, which eliminates outside radio interference that commonly effects the competitions commercial door operator systems that work in the 300MHz radio frequency bandwidth. The transmitters feature silkscreened buttons that clearly identify their functions and the large “ Stop “ button is Red to allow for quick identification for safety. Proudly manufactured in the USA and backed by an 18-month manufacturer’s warranty.