The Plus III trigger has 32 selectable channels (16 standard, and 16 for quad-zone operation) to ensure no interference with other photographers operating in the same area. Four separate zones can be independently selected to allow single or groups of flashes or cameras to be turned on or off. Using the EC-approved 433MHz wavelegth up to a range of 500m, the Plus III operates as a transmitter or receiver, and automatically detects in which mode it needs to operate (e.g. when attached to a camera hot shoe it sets to transmitter). It can trigger a flash and a camera simultaneously: the camera triggering is two stage, a half press of the Plus III button wakes up the camera to meter and focus; press all the way to fire the shutter. Release and the camera will return to sleep mode – a real battery saver. The durable, sleek design includes an internal antenna to reduce bulk, rubberised buttons, and a backlit display which shows battery status, selected zones and channel and operation mode.