Professional set of YATO Allen keys with a hex tip The set is packed in a practical plastic pendant that makes it easier to search for the right key size Keys made of high quality CRV 6150 vanadium steel, characterized by strength and elasticity Allen sort 52-55 HRC hardness. 1. 5 mm 2. 0 mm 2. 5 mm 3. 0 mm 4. 0 mm 5. 0 mm 6. 0 mm 8. 0 mm 10 mm