Kupo suction cups offer a temporary solid light mounting solution on smooth nonporous surfaces. They are great for mounting small lights; cameras and accessories to windows, mirrors, automobiles, boats and any other smooth nonporous surfaces. Because of the excellent rubber material with silicon, Kupo suction cups can be used at temperatures from -12 degrees to 49 degrees c (10 degrees f to - 120 degrees f). A red-line indicator is equippedwarning of any vacuum loss due to adverse shooting conditions. The Kupo 4.5" (11.43 cm) pumping vacuum suction cup with 3/8"-16 thread x 5/8" length. Perfect for mounting a ballhead for car mount shooting. The block is tapped 3/8"-16 threadsX6 around 3 sides which offers flexible and low to surface mounting option.( Supplied with yellow pad protector)