Description: - 4 Pieces kayak drain plugs with 20 pieces kayak tri bulb rivets and waterproof O rings - The drain plugs are used to stop water infiltration and drain the water out of the inner hull of your boat - Aluminum tri-Grip rivet, back side splits in three directions for superior holding power - 3/16" hole size, rivet tool required for installation (not included) grip 1/6" - 1/2" (4mm-12mm) - These rivets will work great on almost any application on kayak like rod holders, pad eyes, terminal ends, handles and so on Specification: Kayak Drain Plugs - Material: PP - Color: Black - Press board size: Approx. 5.4 x 3cm/2.1 x 1.2 inch - Outside diameter: Approx. 2.4 cm/0.9 inch Kayak Tri Bulb Rivets - Material: Aluminum - Size: M5*25 - Length: Approx. 2.3 inch/58.5 mm - Diameter: Approx. 0.38 inch/9.7 mm - Color: Black, silver Package Includes: 4 Pieces Kayak Drain Plugs 20 Pieces Kayak Tri Bulb Rivets (with Waterproof O Rings) Note: Please allow slightly difference due to manual measurement. Color maybe slightly different since different monitor. Thanks!