Wireless RF (radio frequency) remote control for your SFully compatible to Nikon D90. Maximum operating range 100m. Compared to an infrared (IR) remote control, it allows you to operate the shutter from either direction/angle. It supports unique coding for anti-interference and avoiding wrong operation. 3 operations modes: At W Mode; the receiver is active, you can use the transmitter to control the shutter or focus. At O mode; the receiver will be a normal remote switch, and it will not consume any power. At L mode, the receiver will lock the shutter for long exposure (Bulb Mode).