Facom Nut Splitter Set (289.J1) - This set replaces the previous 289 set that had been around for many years. Recommended for automotive and light commercial applications. Set consists of a 289.M8 (8-16mm) and a 289.M18 (16-24mm) in a BP.102 storage case. To split a nut, insert the fastener into the splitter and tighten the wedge screw with a socket or wrench. These sizes specified by both Facom and USAG are a bit confusing. Bottom line is that this set will handle fastener heads or nuts up to 24mm in diameter.
Note - the wedge screw should be kept well greased. Never use an air tool to tighten the nut splitter!