• High-quality alloy drill bits, faster and more precise than traditional ones. • Unique four-blade design for good penetration. • Flat shank for a firm grip without slipping. • Perfect for drilling stone, wood, tiles, plastic, concrete, and plaster. • Compatible with most power tools. • Includes 7 drill bits in sizes 3/4/5/6/8/10/12 mm. • 1/4" hex shank for maximum power transmission. • Dry drilling for soft materials; add water for hard materials.