The L Series plugs have a tapered design with a lift-tab feature to facilitate removal. Great for small size openings and in tight areas where a side tab would not be preferred. Pulling the tab exerts an off-center force which breaks the seal between the plug and wall of the opening.:: a: 0.390, b: 0.456, C: 0.59, D: 0.38, F: 0.59.