TEKTON 23001 4-Inch Adjustable Wrench Drop forged and heat-treated carbon steel construction with a corrosion-resistant satin chrome plated finish Precision-machined slide jaw and worm gear allows for exact fastener fit and smooth adjustment Quick fit jaw opening guide with permanent laser-etched size markings in 1/16 in. and 1mm increments Meets or exceeds ANSI standards 1/2 in. jaw capacity