Surface Drive Plus provides stronger grip on fasteners and nearly eliminates fastener rounding 5 degree ratcheting arc vs. 30 degree on standard combination wrenches Improved comfort - oval shape beam Box end strength improved by up to 20% Up to 20% longer than standard wrenches XL Combination Wrenches are up to 25% longer than standard wrenches. Open end uses Surface Drive Plus} Technology that prevents fastener rounding. Size stamped on both sides and on head for ease in identification.