Item Type: Collet Chuck Holder Model: D20-GT12-110L Material: High carbon steel Purpose: Anti-overload protection to prevent the tap from breaking Taper: 7/24 Hardness: 48 Accuracy: 0.01mm Tapping Range: M3-M16 Tool Handle Length: Approx. 110mm / 4.3in Size of Chuck: Approx. 19mm / 0.7in Maximum Diameter of Tool Holder Taper: Approx. 20mm / 0.8in Extendable and Retractable Stroke: Approx. 15mm / 0.6in Adapter Chuck: GT12,GT12B,TC312,G3 Package List 1 x Collet Chuck Holder 1Builtin spring can help to reduce wear, extend life, bring higher concentricity 2The product is a quickchange tap adaptor, possess large compensation function 3Come with good toughness, strong abrasion resistance, large clamping force, antibroken wire and antichaotic teeth 4Twoway floating of extendable and retractable, effectively improving work efficiency 5The product have antioverload protection function to prevent the tap from breaking