Keystone Heddolf International S220-1KA One Button Garage Door Transmitter The Heddolf S220-1KA is a 310 MHz 10 dip switch remote transmitter compatible with Stanley garage door remotes and receivers. Visor clip Size 3 x 1 3/4 x 1/2 310 MHz frequency 1-Button Single-Channel Remote Transmitter Commonly Available 12 Volt Alkaline Battery