Jacobs Chuck self ejecting key. Nickel thumb grip styles increase leverage and user comfort. Soft steel handles limit the potential for dangerous fracturing under excessive load. Self Ejecting models with spring-loaded ejectors ensure key disengagement after tightening. Never apply extensions, pliers, wrenches or 'cheaters' of any kind to chuck key handles. Do not subject chuck key handles to hammer or other impact blows. 10 teeth. 9/32-inch pilot size.