Neoprene For engine cooling. . .Fits Westerbeke models: 16.0 (50Hz) BEG 16.0 (50Hz) SBEGA 16.0 (50Hz) BED 16.0 (50Hz) BEDA 18.7 (50Hz) SBEG 18.7 (50Hz) SBEGA 20.0 (50Hz) BEG 20.0 (50Hz) SBEG 20.0 (50Hz) BED 20.0 (50Hz) WTA 25.0 (50Hz) BED 25.0 (50Hz) BEDA 25.0 (50Hz) BEDB 25.0 (50Hz) WTF 20.0 (60Hz) BEG 20.0 (60Hz) SBEG 20.0 (60Hz) SBEGA 20.0 (60Hz) BED 20.0 (60Hz) BEDA 22.5 (60Hz) SBEG 22.5 (60Hz) SBEGA 25.0 (60Hz) BEG 25.0 (60Hz) BED 25.0 (60Hz) WTA 32.0 (60Hz) BED 32.0 (60Hz) BEDA 32.0 (60Hz) BEDB 32.0 (60Hz) WTF