Oregon cutting systems. Pro-guard chisel c-loop chain, 78 drive links, chain meets ANSI standards & is UL classified, fits Husqvarna models 33,38, 40, 42, 44, 45, 50, 51, 55, 57, 133, 1405, 154, 234, 238, 240, 242, 254, 257, 340, & 444. Made in the USA.