Efficient, easy to operate, protection -Size: 8 & 9mm, 10 & 11mm, 12 & 13mm, 14 & 15mm, 16 & 17mm, ... work.2. Both metric and inch are available, and each set has two head of different size, can be used to a ... variety size of nuts.3. Can be inserted in ... of nuts will not be rounded, bald angle. Fast open end wrench(Double-headed) set