Features: For the usage of MT shank, taper shank drills, reamers reducing. The reducing drill sleeve is made from high quality 45 steel, sturdy and durable in use. Adopts overall quenching process, long life, lasting, strong shock-resistance. High accuracy, inside and outside are very smooth. Easy to store and maintain, very practical tool. Specifications: Model: 1-2 2-3 3-4 Material: 45 steel Hardness: HRC58 Size: MT1- MT2: length: 92mm / 3.62in, bottom hole diameter: 12mm / 0.47in MT2- MT3: length: 112mm / 4.41in, bottom hole diameter: 17mm /0.67in MT3- MT4: length: 133mm / 5.24in, bottom hole diameter: 23mm /0.91in Weight: 569g Package included: 1 x MT1- MT2Taper Adapter 1 x MT2- MT3 Taper Adapter 1 x MT3- MT4 Taper Adapter Note: Please allow 1-3mm error due to manual measurement. Thanks for your understanding. Package List 1For the usage of MT shank, taper shank drills, reamers reducing 2The reducing drill sleeve is made from high quality 45 steel, sturdy and durable in use 3Adopts overall quenching process, long life, lasting, strong shock-resistance 4High accuracy, inside and outside are very smooth 5Easy to store and maintain, very practical tool