Black or White 100mm inspection cover with "O" ring seal cutting diameter 108mm Requires 6 x 3mm fastenings Hatch covers perfect for Topaz UNO Plus dinghy Inspection covers allow access to remote areas in water tight bulkheads, buoyancy tanks, water tanks etc.  The fully threaded lid with the multi point threaded ring ensures the ability to unscrew in any weather condition. Together with the ‘O’ ring seal for total water tightness. Our inspection covers are a standard within all dinghy manufacturers, though the style has changed over the years the thread mechanism has remained the consistent making upgrading the covers very easy. Lid and ring made from Polypropylene PPH-TD20 ‘O’ ring seal made from Black Nitrile 70 Shore