I used but fairly clean bar mounted Oregon filing guide I believe this clamps onto the bar and enables accurate angle and depth filing and fortunately I don't have any instructions but I'm sure you could find some online please see pictures for design and details of condition and ask if you need any other information or dimensions the file fitted is four millimeters or 5/32" spare file is new and is the same size. please see pictures for details of condition and design and ask if you need any other information or dimensions thank you