This is the new fangled Stihl sharpener. Works and aligns the blade and the rake. Chain sharpening costs $10-$15 a pop. Three sharpenings pays for the file set. Make sure you get the proper size for your chain.
I use an old Husky sharpener. Two 5.5 round files. a flat file and a guide to align files. Throw it in the saw bag and use as needed.