Discontinued piston ring for 1.559 bore diameter Homelite 38 cc Timberman saws and trimmers. One ring per set. Also fits some other models. Selling only the number 4 part ( one piston ring) in the parts breakdown picture above. Please check your bore diameter of 1 9/16" (1.559") or match your model number below. It looks like Homelite has used several different bore diameters in the chart below. Some are 33cc (1.4375"), some at 38cc (1 9/16") and still another at 45cc. This auction is for the medium 38 cc size only. If you have a 23av this should the correct ring as long as you have the medium 1 9/16" bore diameter. I am in the process of getting the 45cc size available soon for that model. If the model number is not listed below you probably need a different ring than this one. Again, please double check your bore diameter before ordering to be sure you get the right size ring. If you check the piston size and it measures larger than 1 1/2" this ring is correct and will fit. See models below.