Please do not create a large buoyancy and the underwater camera system for overall weight to match your preference for a controllable "huro-toa-musisutemu" float arm to arm Body Body Structure, water and weight reduction to advantage, density and light weather resistant ABS material. And the interior of your arm and hollow of your traditional the buoyancy of your arm and deaf compared to ensure success. Ever do to increase weight and buoyancy to your part along the arm, to keep the entire camera system, underwater and efficiently reduce weight at the same time. ,■ buoyancy:-: ■ ■ Effective Length: 150 mm outside diameter: 97 mm ■ body weight (land): 219g ■ ABS resin/耐蝕 Aluminum Alloy/Rubber ■ Practical water resistant depth: 70 m