Scrench, Chain Saw Maintenance & Repair Tool, Combination Screwdriver & Wrench In One Handy Tool, Use To Remove Bar Mount Nuts For Replacing The Guide Bar Or Chain, Use To Adjust Chain Tension, Size: 13MM x 19MM For Use With Some Of The Most Popular Model Chainsaw Brands Such As: Poulan, Poulan Pro, Husqvarna, Stihl, Echo, Shindaiwa, Jonsered & Partner.