The Dot Line 5.75" Vacuum Cup with Ballhead & Quick Release securely attaches to car windows, doors, hoods, and other smooth surfaces and supports camera/accessory loads up to 50 lb. It uses a push-pump mechanism to pump the air out between the cup and mounting surface, and a red line imprinted on the pump lets you know whether any air is left or has seeped back in. The cup is 5.75" in diameter and features a ballhead with a quick release adapter and 1/4"-20 post fixed on top. The quick release adapter removes from the post to let you efficiently attach other equipment. The 1/4"-20 post supports cameras, lights, mics, and other accessories, and the ballhead can be rotated, tilted, and swiveled.
The pump requires just several pushes to get all the air out. With each push, a part of the pump gets depressed inside, less of it protruding on the outside. The point at which the red line on the pump is also depressed signifies that all air is completely pumped out. When the red line reappears, it indicates that some air has entered back in and simply needs to be pumped out again. Two nibs on the edges of the cup let you easily release the vacuum grip. A protective cap is included for avoiding scratches during storage to help maintain suction strength.
