Chainsaw Teeth Sharpener is SAFE as the sharpener is enclosed in a box like kit. It is very EASY and SIMPLE to use: just ATTACH the bar-mount sharpener to the sharp guide bar, the two holes on the top of the bar SECURES the chainsaw and makes a PERFECT ALIGNMENT for and EVEN result. Then just press the tip of the sharpener to a solid surface and allow it to AUTOMATICALLY sharpen your chainsaw in 3-5 seconds.