... head ,countersunk head, round body, hex body, open end, closed end, body with ribben, body with groove. Fastener we use cold forged ... other fittings of industrial products. types: flat head ,countersunk head, round body, hex body, open end, closed end, body with ribben ... 3/16,5/16. material: steel, stainless steel, brass,aluminium. Fastener -rivet nut