The 3-hole butterfly clip design breaks through the traditional style and enhances the use limit of the butterfly clip. The 1-inch ball arm system features 1-inch ball components with a groove and o-ring to prevent slippage for improved holding power with less force. While underwater, clamps may be finger-tightened to keep lighting in place yet allow repositioning without loosening the clamp. All-aluminum alloy hard thickened oxidized surface treatment, more scratch resistant; 304 stainless steel screw spring; wide and large handle, more convenient and easy to rotate, does not hurt the hand. The diving clamp mount for Diameter 25mm ball compatible with arm brands like ULCS, Ikelite, INON, SEA&SEA... Specification: Material: Durable Air-grade Aluminum Size: 55mm*55mm*62mm(L*W*H) Weight: 65g Package Includes: 2 Sets 3 Ball Holes Mount Clamp