Stainless Steel Lag Screw, External Hex Drive, Meets ASME B18.2.1/ASTM F593, 1-1/2" Length, 1/4" Threads (Pack of 100)

Also known as Lag Bolts, Lag Screws come in longer lengths than wood screws and are easy to tighten with a wrench.

Stainless steels are used for their corrosion resistance, high-temperature strength, scaling resistance, and low-temperature toughness.  These properties account for their extremely wide use in practically every industry. Austenitic Stainless Steels are alloys of iron and carbon that contain between 16% and 30% Chromium, a maximum of 0.15% carbon, along with Nickel (or Manganese), and other alloying elements.  The chromium, which helps develop a passive surface oxide film, provides corrosion resistance in stainless steels.   Austenitic Stainless Steels are designated by a 3 digit SAE Stainless Steel Grade beginning with the number 3 (e.g. 304, 316).  Another common naming convention for Austenitic Stainless Steels are 18/8, 18/10, 18/0, etc. where the 18 refers to the % of Chromium and 8 to the % of Nickel contained in the material.    

Hex head fasteners can be driven with simple wrenches, and require minimal clearance above the fastener because they can be driven or loosened from the side.