14129 Westerbeke Heat Exchanger. 14129 and 14129CN are the same part, both with a Copper Nickel bundle. Equivalent to 11966 Westerbeke Heat Exchanger 1380-1-5 or 1380-1-7 Sendure 1279-1-5 Sendure Engines: Westerbeke 40 1975 Also fits Perkins 4-107 and 4-108 W40 or W-40
This part has two configurations sold as the 14129CN and 14129-14CN. Take a look at the pictures to assure you're purchasing the right one. Both are approximately 14 inches long, but the hose configurations are quite different. They assuredly are NOT interchangeable.