These metric combination wrench sets have a 12-pt. box end with additional grooves that make it easier to connect with the head of the fastener and connect at more angles for better accessibility compared to a 6-pt. wrench. The opposite side has an open end design that allows top and side access to the fastener compared to the box end that can only access a fastener from the top. These wrenches have the same metric size on each end for use on one specific size fastener.