This 15mm Rod Clamp with Multiple Threads and 1/4"-20 Screw with a black locking lever from CAMVATE has a single rod port that is compatible with standard 15mm rod systems. The aluminum and steel clamp features multiple 1/4"-20 threaded mounting holes on each side to add accessories such as monitors, lights, or other gear to your 15mm rods, and a single silver 1/4"-20 screw adapter is included.