Poulan O-Ring part# 019141 supersedes to part# 530-019141. This O-Ring is listed as "No Longer Available" by the manufacturer. This ring has an outside diameter of approximately 1-1/4" and was used on the fuel cap of the following two chainsaw models; 4200 and 5200. There may be models that use this part that we do not have listed here. Please refer to your owners manual or a parts breakdown for your model, to assure that this is the correct part for your machine, before you order.