This device has been engineered for supporting probes or very light weight antennas/horns. It screws into the standard NCTM apex or any of the extender rods with a 7/8unf receptacle. A sturdy friction grip allows any angle between 0 and 90 degrees to be maintained without slipping. Top screw interface is a ¼”UNC plug. Length straight: 11.2cm. Diameter: 3.8cm.