Keel Cooler condensers require a K35 or K50 compressor or a Capri 35 or Capri 50 compressor.
Keel Cooler condensors are constructed in marine grade bronze and cupro-nickel. Both models require a 1 1/2” hole for mounting. The exterior parts are identical.
It is a requirement of any installation that the keel cooler be connected to the battery negative as a safety measure. This normally will connect the keel cooler to the bonding system and also the shaft or hull zinc which will protect the keel cooler.