This unit is designed for 5 in. diameter poles and is used with rope style internal halyard systems. Each unit consists of a hinged door mounted to the front of the frame and a cam cleat (optional) mounted to the back of the frame. The entire unit is inserted into the flagpole shaft and secured with ten 1/4 in. -20NC stainless steel screws. Lock & keys included. Silver door and frame unit pictured.