Professional-grade axle nut socket gives ultra-flexibility and tightness. All sockets are made of Chromium Molybdenum (CR-MO), with black phosphoric acid coating on each socket surface, which greater shatter-resistant, rust stains prevention than those made from CR-V steel. Each has highly visible laser-etched marking for easy identification even in low light conditions. 6-point flank drive for tight hold without damaging fastener corners. For easy removal of axle shaft nuts to meet your job requirements.