So what you are going to need to know is the pitch of each chain you plan on sharpening. The pitch will be .325, 3/8, 3/8 low profile etc. If you know that information then you could go to the stihl dealer and get the correct size file for the chain pitch you plan to sharpen. Each pitch uses a different size file. If you look at my post earlier the stihl FF1 is also chain pitch specific because it sits between the rivets on the chain. What you posted will work but the Stihl FF1 with the file kit is what made me consistent in my angles. If you don't like your local stihl dealer try a different one. You can look them up online. The one I bought my saw from was clueless. Once I became educated I went to a different dealer and couldn't be happier as his prices are good and he carries everything you could possibly want. Where are you located one of us may be able to get you to a dealer worth going to. One thing about the stihl file kit and FF1 file guide holder is the files and other parts are top notch files and will last a long time. I bought an off brand file to try similar to what you are looking at and the file didn't hold up nearly as long as the stihl files I was using.
Just my experience, but I'd NEVER go for any filing tools specific to a chain type. Stuff gets lost in the woods.
After sampling a variety of filing guides, I found Granberg's "File-N-Joint" (aka "FNJ"). Been using one about 35 yrs. Once you dedicate a little conscious thought, results are precise & repeatable. Except for debris contact, 1 stroke/tooth every other fill-up and the cutters stay like razors. I like K.I.S.S.- 5/32" & 7/32" files for the 3/8" and 3/16" for .325" pitches, available anywhere. FNJ also does depth gauges precisely with a flat file, BUT using one long-term on a chain, I find that I almost never have to touch them. They wear down at a rate essentially corresponding to the receding of the cutters.
Best to find someone who can show-and-tell on filing. A year or so back, I did that with a couple buds who were struggling with the chain filing stuff they had. I demo-ed theory and practice of filing with FNJ. Maybe 15 minutes for each. Made a huge difference in their chains, which makes a huge difference in longevity of chains, bars, engines.
Sorry but those HF grinders are pure poo. Northern's is orders of magnitude better, but there are prerequisites for getting good results.
For FNJ, NT's price is now about 1/3 off Bailey's. Dunno why Bailey's suddenly jumped $10.