Tecomec Micro Jolly Bar-Mounted Battery Grinder MJ 10.8Tecomec Micro Jolly MJ 10. 8 Battery Powered Bar Mounted Chainsaw Chain Grinder (AU NZ 10. 8 V + 230 V Charger) 5 Year Warranty 10. 8 V Li ion ~15 min fast charge The Micro Jolly MJ10. 8 is a portable, bar mounted chain grinder that sharpens on the saw no chain removal needed. Clip it to the guide bar, set your angle and get back to work. Its built for field or workshop use and gives consistent results on round ground chisel and semi chisel chains.