Welcome to our store. If you love Sports and Outdoor Activities ,we will provide what you want, and give your much surprise. Description: - 20 Pieces aluminum rivets and 20 waterproof O rings - Aluminum Body with Aluminum Mandrel - 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: - 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: 20 Pieces Kayak Tri Bulb Rivets 20 Pieces Waterproof O Rings Note: Please allow slightly difference due to manual measurement. Color maybe slightly different since different monitor. Thanks!