This is our Forester Brand Chainsaw Tooth Brush Blade. The blade is very easy to use on a trimmer with a 1" arbor. I am telling you this thing is a beast a cutting brush. You will be able to sharpen the teeth with a standard round file for years of use. We have a 7" and 9" blade available. This listing is the 7". The max speed is 10,000 Rpm's and I will recommend using some leg protection and maybe some anti-vibe gloves with this item. If you have any questions let us know.