[1] Product type: High quality marine grade canvas and upholstery boat cover snap button fastener kit [2] Meterial: Snaps are made of brass and nickel-plated for added durability. The screws are made of 304 stainless steel, which offers good corrosion in bad environment like high temperature, cold weather, and high humidity areas. They have superior rust and the excellent of oxidation , which can long time using and prolong screws lifespan [3] Feature: Studs are available for clamping onto screw or canvas studs for mounting on hard surfaces. The snaps with heavy-duty construction assures a firm grip that will remain secure through years of use All Stainless Parts, superior snap action and holding strength [4] Application: These button snap studs can be attached to wood, plastics and fiberglass, they are strong and great for both indoor and outdoor use, with excellent rust in salt water applications Specification: Color: Silver Material: copper + 304 stainless steel Screw Size: 15x10mm(059 inch x039 inch ), 15x15mm(059 inch x059 inch ) Button cap dia: 15mm/059 inch Package Contents: 40pcs * Socket 40pcs * cap 20pcs * screw(10mm) 20pcs * screw(15mm) 1 * Anvil 1 * Flaring 1 * Storage box Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.