This is for the gravastar mercury x pro mouse its an extender for someone that has bigger hands and wants to play with a relaxed claw grip. You want to use double sided adhesive to keep it on the mouse preferably black to blend in just cut a little piece one on each side. Can print with more walls or infill if you want it thicker one file is a little thicker but if you want it thin and to keep light without adding much weight there is a file there too