I'm looking for just the muffler labelled number 22 on your diagram for a Stihl MS260. Please can you confirm which part I need to buy.

This is the correct muffler for your machine: https://www.lsengineers.co.uk/muffler-stihl-part-no-1121-140-0604.html We do also do a non-gen replacement version which also crosses over with the part number you need: https://www.lsengineers.co.uk/non-genuine-exhaust-assembly-for-stihl-ms240-ms260.html