Middle Atlantic HM500 Premium Rack Screw - 500 Pieces, Black Matte FinishPremium rack screws provide the best bit engagement in the industry. HG hardware features salt spray resistant plating that slows rust build up and is ideal for marine and high humidity installations. HM hardware features an attractive black matte finish. Both types are truss head hardware, 10 32 threaded, 3 4 " long with pre installed washers and self guiding pilot points.