Bowens Multi-functional Transceiver Pulsar Radio Slave Trigger Twin Pack, for Cameras, Flashes and Light Meters Radio Transmitter: Pulsar can trigger devices around corners and through walls. 100m Range: Pulsar allows photographers to work further distances from their light source. It's a Transceiver: Pulsar can be a transmitter or receiver at the touch of a switch. Long battery life up to 200 hours of continuous use from two AAA batteries. Low voltage operation of just 3V making it ideal for use with sensitive digital cameras.