Metric. 4-piece set. Incl. 4 wrenches with an open end on one side and a ratcheting box end on the other side; with identical sizes on both ends. Packed in a robust textile pouch with hook and loop on the rear side. Color coded for size. When everything fails; it''s time to play your Joker. - Open end. The Joker has a non-angled 12-point beak; therefore it requires just 30° of working space; otherwise it functions just like a regular open end wrench. The dark metal plate dual functions as a retainer; preventing the nut to slip through the wrench beak or it holds the nut. 30° further the metal retainer plate allows the nut to slide through; or grip it since the metal plate is equipped with a hardened ragged edge. The teeth of this edge will ''bite'' itself into a rounded-off nut; loosening it where others do nothing but slip-off. - Box end. Comes with a very fine 80 tooth ratchet for a small 4.5° return angle. Ratcheting direction is indicated on both sides. Size: 10mm Overall length: 159mm. Size: 13mm Overall length: 177mm. Size: 17mm Overall length: 224mm. Size: 19mm Overall length: 246mm.