Chain Pitch is the size of the chain, and is defined as the distance between any three consecutive rivets divided by two. Oregon chain is made in several pitches - 1/4" is the smallest, 3/8" is the most popular, 3/4” is the largest. Pitch is important because the drive sprocket must be the same pitch as the chain, and if applicable, the bar nose sprocket. The easiest way to determine the pitch of your chain is to look at the number stamped on the drive link.
3/8"
Sprocket Tooth Count
Sprocket Tooth Count
Your saw may be compatible with various drive sprockets. If this is the case, a smaller tooth-count will deliver more speed, while a larger tooth-count will deliver more torque (useful on smaller saws). Tooth-count may also influence the drive link count on replacement chain.