The Oneway Stronghold Chuck is key operated. Key operation provides one hand operation and superior holding power. The gear teeth are precision machined to guarantee that no teeth skip in use. A 5 to 1 ratio assures powerful clamping. Approximate weight is 8 lbs. External chucking capacity is 2″ to 3-1/2″, and internal chucking capacity is 2-5/8″ to 4-1/8″. The Stronghold Chuck comes with adjusting key and 1-1/2″ WoodWorm Screw.