Features: 1. Each product has a unique manufacturing part number label on the inner package that proves that it has been qualified, which includes the part number, model number and information date of inspection; 2. If you have any question about the item, please provide us the manufacturing part number for checking, your profits will be guaranteed. 3.ER straight rod type pliers extension handle, spring steel pliers with hardening and precision, suitable for deep hole processing.4.Use for motor rod extension, can replace the drill clip, with ER collet perfectly suitable for all kinds of straight shank tools.5.The extension rod is made of 40CR, good quality. , 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm. The traditional ER chuck is easy to lock into the cutter bar when installed and cannot be removed. The eccentric nut is removed with the chuck and cutting tool when the nut is removed. It solves this problem well. Installation steps: 1. Remove the nut and insert the collar