Feature: The patented locking function, the unique traditional locking methods, back having ratchet teeth, the locking parts mounted on the rear sleeve, the peripheral length of the lock, more effective in preventing work lose off, so that the chuck clamping, more reliably support tools. Good metal and comfortable coat surface. Unique thrust torque bearing is easy to handle applied translate into greater clamping force. Chuck Specifications: Material: HSS Drill Chuck Outer Diameter: 40mm Clamping Range: 2-13mm Mount: 1/2-20UNF Allow 1-3mm error. Applicable Scope: suitable 1050w power over impact drill. Package includes: 1x chuck