Red Head Trubolt Type 316 Stainless Steel Wedge 1/2-Inch X 4-1/4 Inch Anchor contains more nickel and chromium than type 304, and two-to-three percent molybdenum, which gives it better corrosion resistance. it is especially more effective in chloride environments that tend to cause pitting. Typical applications include: tunnels, dams, tiles, lighting fixtures, etc. Use these Red Head anchors in a marine type environment with heavy atmospheric pollution. Red Head anchors consist of a high-strength threaded stud body, expansion clip, nut and washer. The expansion clip consists of a split cylindrical ring with undercutting grooves. The exposed end of the anchor is stamped to identify anchor length. Stampings should be preserved during installation for any subsequent embedment verification. Specs: Thread Length (inch) -- 2-3/4; Anchor Diameter and Drill Bit Diameter (inches) --1/2-Inch - 13; Overall Length (inch) -- 4-1/4; Max. Thickness of Materials to be Fastened (inch) -- 1-1/2-Inch; Quantity per Box -- 25.