A lot of the Husqvarna's have the same m8x1 flywheel side thread so that part works on several models. PTO side thread on a few, but the older ones you would need to buy a few more. For the price of the OEM tools, just buy a couple and the range of models covered does expand. For example the 272's M10x1 flywheel side also works on saws like the Stihl ms660. So yes they will work on models other than their specific design, and yes a few of those OEM's can cover a lot of the Husqvarna saws as well as some from other brands. The Husqvarna OEM shop tools are by far the most cost effective options out there.