Compatible with standard 15mm camera rig rods and can be used with most 15mm rig systems. This 0.6 inch (15 mm) rod clamp allows you to attach shooting accessories such as monitor arms and mini heads. There are 3 1/4 female screw holes on the top, front and back, allowing you to mount various accessories to suit your shooting needs. You can take the perfect photo faster, smart and fast. Thumbscrews that secure 0.6 inch (15 mm) rod are ratcheted, so you can move them to the perfect angle. When securing the camera and parts securely, even if the knob is interfered and the screw cannot be rotated, the knob can be opened and tightened.