NeoBurrĀ® RA 4SL Surgical Length Round Carbide Bur by Microcopy (USA). Engineered from a single piece of solid tungsten carbide with an extended surgical length right-angle latch shank (RA SL) and a 1.4 mm round cutting head. Specifically designed for low-speed surgical handpieces, slow-speed bone guttering, apicoectomy, root resection, and deep caries removal near the pulp chamber where high-speed turbine exhaust air must be avoided to prevent surgical emphysema.