Chainsaw Chain 20 Inch for Stihl .325 Pitch, 81 Drive Link, .63 Gauge, Low Kickback Replacement chain for Stihl For 20 inch bar 81 drive link, .63 gauge, .325 pitch Avoid cutting into dirt, concrete and any metal materials For professional use and the ones who have experience to use chain saw only Design to cut wood/trees only. Always keep saw chain right tension