The radio transmitter KYMASGARD® FK1 - FSE is a battery-less and maintenance-free window contact with one channel. Energy generation is effected by conversion of indoor room light into electric energy by means of a solar generator. It is used for status monitoring of windows and doors employing a reed contact with counter magnet, and for transmitting the results via radio signal to radio actuators and radio receivers ⁄ gateways. It is suitable for mounting on window and door frames made of wood, glass and aluminium.