New in the box STIHL OILOMATIC chainsaw chain. fits a 20 inch bar. It is .325 chain .063 gauge and it has 81 drive links. it fits most 026, 027, 028, 029, ms 260, 270, 280, 290, 261, 271, 291, ect, PLEASE FEEL FREE TO MESSAGE US. WE CAN HELP YOU FIND THE RIGHT CHAIN FOR YOUR SAW. This is the yellow chain that is aggressive. ALSO KNOW AS PART NUMBER 3639 005 0081 36390050081