The STIHL 3639 005 0068 (26RS 68) 18" length, .325 pitch, .063 gauge-68 drive lengths is made for the most demanding cutting conditions and is loaded with professional features. Stihl chain has Oilomatic drive link lubrication slots, which funnels oil directly to the rivet to reduce wear. Stihl chain is also pre-stretched at the factory, which helps eliminate excess adjustments during break in periods. 26RS is part of the Stihl Rapid Super series. 26RS is a fast cutting chisel chain which work best in clean cutting conditions, where there is limited contact with dirt and other abrasive materials. This is a yellow labeled saw chain. This product has increased risk of kickback injury and is for use only by persons with extraordinary cutting needs and experience and specialized training for dealing with kickback. DO NOT USE THIS SAW CHAIN UNLESS YOU HAVE EXPERIENCE AND SPECIALIZED TRAINING FOR DEALING WITH KICKBACK.