These "N" Series THICK WALL CORE BITS have a Rope Thread shank and a "A" TAPER starter bit.

Thick Wall Percussion Core - used to bore large diameter holes in brick, block, masonry, and concrete. The "inside" core depth is 5" Thick Wall cores are extremely durable and can be re-tipped. The thicker core wall results in longer life, yet slower drilling time. Thick wall core bits are made to be used with larger roto-hammer drills only. Deep holes in concrete require romoval of core particles.