1.Drop forged and heat-treated carbon steel construction with a corrosion-resistant satin chrome plated finish. 2.Quick fit jaw opening guide with permanent laser-etched size markings in 1/16 in. and 1mm increments. 3.Precision-machined slide jaw and worm gear allows for exact fastener fit and smooth adjustment. 4.1 in. jaw capacity. 5.Proportioned dimensions for the greatest strength and minimum weight