Features 1、Good electrical conductivity and thermal conductivity. 2、570pcs solid copper sump plug washer set for multiple choices. 3、All contained in a compact and see through compartmented plastic case. 4、Great for sump plugs, water, fuel and hydraulic fittings. 5、A sump plug washer set to suit all types of engines be it Car, Marine, Generators, Machinery and Plant. Specification Description: These spring collets are made of high quality 65Mn spring steel for CNC milling lathe tool and work-holding engraving machine. There are total 10 collets of various sizes in on set which can basic meet your need. Collet must be placed into collet chuck nut before inserting into collet chuck. Features: Made from high quality 65Mn spring steel, they are stable in performance. Fine workmanship, good elasticity, high precision and run-out tolerance is 0.03mm. Collet must be placed into collet chuck nut before inserting into collet chuck. Each collet is marked clearly so you can easily distinguish them. Great collet for CNC milling lathe tool and work-holding engraving machine. Specifications: Material: 65Mn spring steel Model: ER20 Range: 3mm, 1/8", 4mm, 5mm, 6mm, 1/4", 8mm, 10mm, 12mm, 1/2" Height: 30mm OD: 15mm Run-Out Tolerance: 0.03mm Package Includes: 10 x Collets Package List