Oregon 3/8 Rim Sprocket 509604X ST 7-7 – For Stihl 038, MS380, MS381

Oregon rim sprocket. Check the drive rim regularly for wear. Grooves get worn into the drive slots and over time these can become excessive which then leads to damage to the chain drive links. This then causes rapid widening of the guidebar groove. Rims are cheaper and easier to replace than spur sprockets.