This Impact Bit Holder features a 3/8" (10 mm) machine insertion and a 1/4 (6.3 mm) hex bit socket, providing secure bit retention and efficient torque transfer for demanding fastening tasks. Its 33 mm length offers optimal accessibility and control, making it suitable for professional industrial applications. Key features: - Machine insertion size: 10 mm (3/8") - Hex bit socket size: 6.3 mm (1/4") - Length: 33 mm for enhanced maneuverability - Durable construction compatible with impact tools - Ensures reliable performance without magnetic or quick-change functions