Atlas Copco Secoroc's Premium Plus DTH bits are engineered to address shanking and chunking problems. The new Premium Plus bits are designed to improve fatigue properties. The buttons have been repositioned and protrude more. The new Premium Plus range starts with bits for 5-inch hammers, with bits for 3- and 4-inch hammers to follow. The bits are available in a variety of configurations. Atlas Copco Secoroc, Card No. 70