Used twice after purchase. SLIK Plate II (6091) A plate made of sturdy aluminum die-cast. It is attached to a tripod or a panhead to mount two cameras. The tripod (panhead) mounting screw is U1/4 inch screw (small screw), and the camera mounting screws are two U1/4 inch screws, employing a "double nut type" that securely fixes the cameras. To mount two cameras, use a tripod with a pipe diameter of around 28mm or more, such as a "medium" size or larger model (Master III, Carbon Master 814 PRO II, etc.). Attachment to the tripod also supports U1/4 inch screws (general camera mounting screws [small screws]). Size: Length 315mm x Width 50mm x Height 20mm (excluding screw part) Weight: 500g Camera mounting method: Double nut type