Easy Installation: The square hole drill bit adapter mortise tool is easy to install and remove. Easy to Use: A professional woodworking tool, the square hole drill bit adapter bracket enables accurate and smooth drilling. Fitment: This square hole drill bit adapter is compatible with corded hand electric drills only. It is not compatible with bench drills or cordless (rechargeable) hand drills. Note: The square hole drill bit fixing bracket is designed to clamp the exposed portion of the electric hand drill with a width of approximately 20 mm (0.79 in) and a diameter of 38–43 mm (1.50–1.69 in). Please verify compatibility before use. Product Size: 5.3 cm × 15 cm (2.09 in × 5.91 in) Color: Silver Material: Aluminum alloy Package Contents: 1 × Drill bit fixing fixture Note: Color representation may vary slightly due to lighting conditions and screen settings. Measurement tolerance is ±1–3 cm.