SpecificationRound Head Size: 4mm / 0.16"Base Diameter: 6.5mm / 0.26"Height: 7.5mm / 0.3"Package Content: 90 Sets x Ball Head Screw Stud 4mmFeaturesButton Studs: The two parts of the round head rivet fit tightly, and it is firm and does not shake after installation. The studs are centered and the screw's Phillips slots are thin for a nice appearance and interior surface.Sturdy Material: Made of quality alloy, wear-resistant and anti-rust. Fine workmanship, smooth edges without burrs. The surface is anti-oxidation treatment with electroplating process, which keeps the luster more lasting, does not easy to fade and bright as new, can be used for a long time.Easy to Use: We have equipped with a punch and a screwdriver for your installation.