[1] Product Type: High-quality marine-grade boat cover snap fastener kit for canvas and upholstery [2] Material: The snaps are made of brass and nickel-plated for increased durability. The screws are made of 304 stainless steel, providing good corrosion resistance in harsh environments such as high temperature, cold weather, and high humidity areas. They have superior rust resistance and excellent oxidation resistance, ensuring long-lasting use and extending the lifespan of the screws [3] Packaging: In this kit, we offer 40 sockets and 40 buttons, 15x10mm (0.59'x0.39') and 15x15mm (0.59'x0.59') screws each 20 pcs, along with 2 mounting tools stored in a transparent plastic box, convenient for storage and use [4] Function: The studs can be used to clamp onto screws or canvas studs for mounting on hard surfaces. The snaps with robust construction ensure a firm grip that will remain secure over the years. All stainless steel parts, superior snap function and strength [5] Application: These button snap studs can be attached to wood, plastic, and fiberglass, they are strong and excellent for both indoor and outdoor use, with excellent rust resistance in saltwater applications