I can see two Festool tools item numbers, is the tool the same? if so, what's the difference ? eg ETS 150 EC , current 576333, replaces 575049

Great question! if the tool name is the same, then the Systainer has been changed from a Tloc to a Sys3 version - same tool inside! The main difference is most Sys3 systainers now have an handle on the side, as well as top.