The PROMASTER SystemPRO Wireless Remote Shutter Release uses Radio Frequency to trigger the shutter release of the camera. By using RF, you can trigger your camera from up to 100' away and without a line-of-sight limitation. The PROMASTER SystemPRO Wireless Remote Shutter Release allows you the freedom to operate your camera's shutter without having to touch or be near your camera. Unlike wireless infrared, this RF remote does not require line of sight to the camera and is not subject to adverse lighting conditions.