This is Husqvarna's High-Performance, Low-Vibration Chain.Square-corner "chisel" cutters. Ideal for use on 35cc to 60cc saws. Requires Less Power From The Saw. Cuts a narrower kerf than standard chains. Low-Vibration & Low-Kickback. Gain more control while you're cutting. Chamfer Chisel. Cut cleans and fast. Fits Husqvarna models: 545 Mark II and 550XP Mark II