The Irwin 4" Long Spade Flat Drill Bit Speedbor Set includes seven high-performance spade bits designed for fast and efficient wood drilling. Each bit features a patented Blue-Groove? cutting edge that allows for aggressive removal of wood chips, ensuring faster drilling and cleaner holes. The chamfered cutting edges increase durability, while the extra-long 16-inch length provides extended reach for deep drilling applications. Ideal for use with impact drivers, this set is perfect for both professional contractors and DIY enthusiasts. Features Patented Blue-Groove? Cutting Edge: Ensures faster chip removal and drilling speed. Chamfered Cutting Edges: Increases durability and reduces splintering. Extra-Long Length: 16-inch length for extended reach in deep drilling applications. Impact Rated Shank: Designed for use with impact drivers for enhanced versatility. Durable Construction: Made from high-quality steel for long-lasting performance. Optimized Point Tip: Minimizes splintering and controls speed for cleaner holes. Specifications Brand: Irwin Model Numbers: 87924 (1 1/2"), 87920 (1 1/4"), 87916 (1"), 87914 (7/8"), 87912 (3/4"), 87910 (5/8"), 87908 (1/2") Diameter: 1 1/2", 1 1/4", 1", 7/8", 3/4", 5/8", 1/2" Length: 4 inches each Material: Steel Shank Type: 1/4-inch impact rated