Material: Black nylon plastic, Size:Stem Lenght Approx:13mm Fit into 10mm/0.39inch Hole Head Diameter Approx:20 mm Good Quality: Anti-wear and anti-corrosion, would not break or crack easily during use. Universal: Fit into 10mm / 0.39inches hole, hold your parts very tightly. Great for Door Trim, Car Fender, Bumper, Side Skirt, Radiator Shield, Splash Shield Retainers. Push-type Design:Push in type, rivet post pressure expands legs for fast and tight fastening. Easy to fasten Bumper Fender Flare and Mud Flap. Thank to this design, no need to go to an auto parts store, save time and money. Package include: 40 pcs push type rivet.