This drill bit extension screwdriver is designed for versatile use in confined spaces. It features a hexagonal shank bit with a 6.35 mm (1/4 inch) joint section and is made from metal and plastic alloy. The package includes 4 pieces in multicolor, suitable for both hand drills and electric drills. Note that color may vary slightly due to monitor , and measurement errors are within +/- 1-3 cm.