7 keys. 1.5 mm. 2.0 mm. 2.5 mm. 3.0 mm. 4.0 mm. 5.0 mm. 6.0 mm. Industrial quality. This quality Eklind Fold-Up Hex Key Set is the industry standard, and manufactured using the higest quality Eklind Alloy Steel. It is hardened, tempered and finished to resist rust. All Eklind keys meet or exceed ANSI B18.3 and Fed. Spec. GGG-K-275D. www.eklindtool.com. sales(at)eklindtool.net. Made in USA.