RFN-4 (RF-907) Wireless & Cable Shutter Release for Sony and Minolta DSLR (Sony Alpha A100, A200, A300, A350, A500, A550, A580, A700, A850, A900, SLT-A33, SLT-A55, SLT-A57, SLT-A65, SLT-A77VM) RM-L1AM Both Wired Cable Release and Wireless Remote Control Shutter Release. Maximum range of 260 feet or 80 meters. 16 selectable channels in 2.4GHz operating frequency. Bulb mode function. Conveniently uses AAA batteries in both Receiver and Transmitter.