Hex cap screws are often mistakenly called hex bolts, though the main difference is that hex cap screws feature a washer face under the head and a chamfered point, and a hex bolt does not have a washer face or chamfered threads. A hex head cap screw is a six-sided bolt with a trimmed hex head and a washer face on the bearing surface. These stainless steel hex cap screwws meet specific tolerances as described under ASME B18.2.1-1996. Hex cap screws are commonly used in OEM applications where precise tolerances are needed. Hexagon head designed to be driven by a wrench or socket. Called hex cap bolts or hex cap screws. 18-8 Stainless steel hex cap screws offer protection from weather and corrosive environments, Rust resistant in fresh water environments. For salt water environments use the 316 stainless steel version