Doran DV 99 8x8" Light Tight Darkroom Louver for D 68 and DVM 199 Fans Wein The Adapter plate screws into Featuring a cardioid polar The Adapter plate screws into your tripod socket and has a 1 4 20 tripod thread on the bottom so you'll always be able to attach your camera to a tripod without removing the strap a real benefit when the shot calls for added stability or a slow shutter speed As a compact traveler tripod Each Doran Light Tight Darkroom Louver is designed to supply just the right amount of air to a particular model exhaust fan If there is no air supply to the darkroom the fan will be working against a vacuum and can do nothing