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 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. I'll be stocking the USAG version of this set (tools are identical....tray is different) as it's considerably less expensive and comes with a US warranty.
Note - the wedge screw should be kept well greased. Never use an air tool to tighten the nut splitter!