Made of high quality spring steel, they are stable in performance fine workmanship, good elasticity and high precision Collet must be placed in collet nut before inserting into collet chuck Each snare is well packed in separate protective container with label For CNC milling turning tool and magnet engraving machine Features: These spring rings are made of high quality 65Mn spring steel for CNC lathe tool and engraving machine. There are total 15 pliers of different sizes on the set, which can meet your basic needs. Each clamp is well packed in a separate protective container with a label so you can easily tell them apart. The collet must be positioned in the collet nut before inserting it into the collet. Technical specifications: Material: 65Mn spring steel Range: 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 1/8", 1/4 Height: 18mm / 0.7" OD: 10mm/0.39" End of stroke tolerance: 0.008mm Weight: 127g (approx). The package includes: 1 set (15 pieces) of