The RT-32 Radio Transmitter Module plugs directly into a built-in compartment behind the battery door. Compatible with the L-358, L-608 and L-608C, the Transmitter module triggers the electronic flash units wirelessly as the meter takes a measurement. Channel ID's are easily selected through the meter's built-in software (CH 1-16 Single Remote Triggering, CH 17-32 Remote control "Quad Triggering"). Compatible with PocketWizard Digital Radio Slaves.