Easy Installation: The square hole drill bit adapter mortise tool is easy to install and remove, allowing for quick self-installation. Easy to Use: A professional woodworking tool, the square hole drill bit adapter bracket enables accurate and smooth drilling. Compatibility: Designed for use with hand electric drills only; not compatible with bench drills or cordless hand drills. Specifications: The drill bit fixing bracket accommodates the exposed clamping portion of an 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 dimensions before purchase. Dimensions: 5.3 cm × 15 cm (2.09 in × 5.91 in) Color: Silver Material: Aluminum alloy Package Includes: 1 × Drill bit fixing fixture Note: Color may vary slightly due to lighting and screen settings. Measurement tolerance: ±1–3 cm.