1 channel DTMF key switch This kit lends itself to countless applications where remote control ( bistable or monostable ON / OFF ) of any electric - electronic circuit is required.  It can be connected to the BF output of any UHF, VHF, HF receiver or transceiver or to any low frequency line.  Characteristics Bistable operation Monostable operation User manual included Dimensions: 52x35mm Vendor Code: 543-0428 It uses an IRL520SPBF transistor Absorbed current with relay at rest: 10mA Current absorbed with relay energized: 30mA Variable voltage from 8V to 13.8V VR1 resistive trimmer