This Cover Seal is used on the Hydronic S3 water heaters, both the CL & CS versions.
Note: Not compatible with Gas versions of the CL Heaters P/N's: B4E 20.1963.05, D4E 25.1994.05 & 25.2049.05, B5E 20.1952.05., D5E 25.1993.05 & 25.2048.05. These heaters use P/N: 20.1952.99.0105.