Tough, durable Cubitron based Regalite abrasive on Y weight cloth backing. Self sharpening Cubitron sol gel mineral creates sharp new cutting edges as it wears for high cut rates, long life, consistency, increased productivity and fracture toughness. Higher stock removal with less heat and loading.The DEWALT DW1587 6 Bit 3/8-Inch to 1-Inch Spade Drill Bit Assortment includes six commonly used high-performance drill bits to complement your tool set. The set features the Max Life corner that preserves nail life, the Extreme Speed Channel for efficient chip removal, and a 1/4-inch ball groove shank for quick bit changes. DEWALT spade bits are designed with heavy-duty shanks for extended life and durability.All DEWALT spade bits are designed with cutting spurs for optimum hole finish, a hang hole for bit storage & wire pulling, full length heat treat for longer life, flats on shank to prevent slipping in chuck, 1/4-inch Quick Change shank which fits all drills, and 1/4-inch quick change holders.