HIPA Air Filter Assembly with 2 Replacement Foam for STIHL 021 023 025 MS210 MS230 MS250 Chainsaw Fitment models: STIHL 021 023 025 MS210 MS230 MS250 chainsaw Package include 1pc air filter foam, 2pcs replacement filter foam A dirty air cleaner will restrict air flow to the carburetor, reducing engine performance, causing rapid engine wear Replace air filter often