SEALING RING FOR STIHL CHAINSAW DRIVE SHAFT MODELS: 017 , 018 , 019 T , 021 , 023 , 025 GS 461 , MS 170 , MS 171 , MS 180 , MS 181 MS 190T , MS 210 , MS 211 , MS 230 , MS 231 MS 250 , MS 251 , MS 270 , MS 271 MS 291 , MS 280 , MS 311 DIMENSIONS: OUTER DIAMETER: 25 mm INTERNAL DIAMETER: 15 mm WIDTH: 5 mm Part No.: 40271764 Original part No.: 9638 003 1581 MP