Stryker's FORMULA series contain technology advances that increase sharpness, enhance suction and tight tolerances for optimal performance. The 6-Flute Left Helix Barrel speciality bur, a part of the Stryker FORMULA series, uses a reverse rotation combined with its left helix flute to draw the bur into the bone during bone resection. This eliminates the bur head from skipping off of the bone and enables surgeons to use the same technique on right and left joints.