Perfect fit for my old antique HOMELITE XL-12 chainsaw. Took quite a while to arrive, but worth the wait. The old sprocket was deeply indented and the chain was jamming in the grooves of the metal teeth. Now my old reconditioned 50cc chainsaw rules again.....WAY out-torqueing my 32 cc STIHL at much lower RPM's. I ordered two of these to have a spare, but it looks like this spur will to last a long time (the old sprocket was the original spur that came with the XL-12 in 1974). Piece of cake to install by first immobilizing piston movement using a wooden dowel inserted into the exhaust port (afer removing the muffler). The enclosed bearing fits perfectly and limits sprocket vibration. I'm thrilled to have my very noisy, vibrating, old manual oiler chainsaw back in action....great machine!