US PRO 4pc Nut Splitter Set Features: For the removal of damaged or corroded nuts without damaging the bolt thread Hardened Chrome Molybdenum Steel blades and forged grips for strength and durability Specification: 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