Im 79 and when I was commercially cutting timber back in the 1960's I used MacCollough saws and I sharpened the chain three times a day, needless to say I was darn good at sharpening, at my age I need a little help and this simple gadget really helped, I wish the instructions were a bit more detailed.
You may wonder why I had to touch up the chain so much, I was cutting cypress while standing in three foot deep water, ten hours a day, wasn't allowed to cut anything on land.
Cypress is full of water, I averaged 112 trees a day, cut, trimmed and sawed to required lengths. (Snow fence).
Rip saw sent it quickly and I plan on purchasing a bar and chain for my Husqvarna 327xp.