Features: 1.Multi Channels to avoid interference AC-01B: 1 channel AC-04B: 4 channels AC-16B: 16 channels 2. Receiver with sync cable, specially used for studio flash 3. Sync cable for studio flashes 4. Transmitter -- 12V-23A 5. Receiver power source: AC110V-240V 6. Working frequency:433MHz 7. Max. working distance--30m (Open area without interference) 8. Max. Sync Speed - 1/200 - 1/250s (depending on camera and flash) 9. Works for majority of older flashes used with film cameras.