544555 Oregon chainsaw saw sprocket 1/4 pitch conversion
The 544555 Oregon chainsaw sprocket conversion with a 1/4 inch pitch is compatible with the Echo CS-280, CS-290, and CS-300EVL models, allowing for the use of a 1/4 inch mini carving bar and chain.
Check bar and chain for info to confirm if you have 1/4 pitch like this sprocket.
1/4 pitch 8 tooth crank shaft diameter is 0.315
Part# for additional bearing is 22152