Tunnel Bits are ideal for drilling deep, large holes in brick, block, and concrete with SDS Max rotary hammers.Idea for drilling large holes where the depth of the hole exceeds the practicality of a core bit. Premium carbon steel, heat-treated, improves core strength for maximum durability and extended life. Fast penetration rate thanks to the chisel-shaped carbide teeth.Wide lands and substantial core thickness make the bits durable even in large hammers.Centering tip reduces bit walking for exact spot drilling.The centering tip reduces bit wandering for precise spot drilling. Compatible with all SDS-Max style chucks.