For the removal of damaged or corroded nuts without damaging the bolt thread. Hardened CR-MO steel blades and forged grips for strength and durability. This sets size range is 9 to 27mm. Sizes shown are the minimum to maximum diameter between which each nut splitter can be adjusted. Size 1 Splitter: 9-12mm (Length 76mm) Requires 13mm spanner to operate Size 2 Splitter: 12-16mm (Length: 95mm) Requires 17mm spanner to operate Size 3 Splitter: 16-22mm (Length 125mm) Requires 22mm spanner to operate Size 4 Splitter: 22-27mm Requires 24mm spanner to operate