SELF BAILER BUNGS TENOB large nylon self bailers feature a nitrile one-way diaphragm which is unaffected by petrol diesel or oil. It also includes a bung sealing plug. The self bailer is available in 2 versions. External mount - mounts externally outside the boat as with normal drain plugs for standard self-bailing. Internal mount - mounts internally on the boat : ideal for cockpitn raining and for dinghies and inflatables as plug is readily accessible.Flow rate - 500 litres per hour.,Colour - black.,35mm I.D drain hole.,Drill a 41mm mounting hole