Quality and perfect tool for leather craft Material: Stainless steel ( 420J2 ) , HRC : 55 Size No 0 : Blade width 0.6mm , Suitable for 0.4-1.3mm thickness above medium hardness of leather Size No 1 : Blade width 0.8mm , Suitable for 1.0-2.0mm thickness above medium hardness of leather Size No 2 : Blade width 1.0mm , Suitable for 1.6-2.6mm thickness above medium hardness of leather Size No 3 : Blade width 1.2mm , Suitable for 2.2-3.2mm thickness above medium hardness of leather Size No 4 : Blade width 1.4mm , Suitable for 2.7-4.5mm thickness above medium hardness of leather Size No 5 : Blade width 1.6mm , Suitable for 3.2-5.