[Brackets Holder] The Mount Base surface length about 14.2cm(5.59inch), the center-to-center distance between the two mounting holes is 1.97'' (3.5cm) and 5.31'' (13.5cm); detail size-please kindly check “FIGURE 2”. 4*bolts, 4*nuts and 4*washers locking nuts (4-Hole) are included to make installation fast and easy, it is a secure and solid base. [Compatibility Bracket] BRACKETS SUGGEST using LENGTH of 16cm(6.3'') to 30cm(11.81''), LESS THAN 30cm(11.81''). The Mounting Brackets Holder working for Dash Mount, Mobile Radio Brackets, Grid Brackets, GPS Fish Finder Vehicle Mounting Plate etc. [Wide Compatibility] The bracket holder Compatible with Car Cup Holder Bracket, Air Vent Clip and Suction Cup Mount, monopod, selfie stick and any tripod with standard 1/4"-20 threading. The mount are made of ABS material; sturdy, durable, rust-proof, anti-corrosive, non-slip and waterproof. [Compatible with RAM mount B Size ball head] 25mm (1-inch) ball adapter( Standard 1 inch / 25 mm mounts). Compatible with 1 inch / 25 mm / B size mounts, 1 inch ball adapter can be rotated 360°, free to adjust the horizontal or vertical direction. [25mm (1-inch) ball adapter] High quality handheld radio holder with 1" ball head adapter body is made of aluminum alloy, the surface of anodic oxidation treatment, durable anti-corrosion and anti-rust, suitable for a variety of harsh environments, is the motorcycle/ ram/bike holder/kayak /ball mount etc for long-term use of the ideal choice. [Brackets Holder] The Mount Base surface length about 14.2cm(5.59inch), the center-to-center distance between the two mounting holes is 1.97'' (3.5cm) and 5.31'' (13.5cm); detail size-please kindly check “FIGURE 2”. 4*bolts, 4*nuts and 4*washers locking nuts (4-Hole) are included to make installation fast and easy, it is a secure and solid base. [Compatibility Bracket] BRACKETS SUGGEST using LENGTH of 16cm(6.3'') to 30cm(11.81''), LESS THAN 30cm(11.81''). The Mounting Brackets Holder working for Dash Mount, Mobile Radio Brackets, Grid Brackets, GPS Fish Finder Vehicle Mounting Plate etc. [Wide Compatibility] The bracket holder Compatible with Car Cup Holder Bracket, Air Vent Clip and Suction Cup Mount, monopod, selfie stick and any tripod with standard 1/4"-20 threading. The mount are made of ABS material; sturdy, durable, rust-proof, anti-corrosive, non-slip and waterproof. [Compatible with RAM mount B Size ball head] 25mm (1-inch) ball adapter( Standard 1 inch / 25 mm mounts). Compatible with 1 inch / 25 mm / B size mounts, 1 inch ball adapter can be rotated 360°, free to adjust the horizontal or vertical direction. [25mm (1-inch) ball adapter] High quality handheld radio holder with 1" ball head adapter body is made of aluminum alloy, the surface of anodic oxidation treatment, durable anti-corrosion and anti-rust, suitable for a variety of harsh environments, is the motorcycle/ ram/bike holder/kayak /ball mount etc for long-term use of the ideal choice. ‌