This Collins Collins 354A-1 NOS Filter Deck, is to Convert the 51J-2 / 3 to a 51J-4 P/N 522-9046-002
This Deck will convert the 51J-2 /3 and R-388 to a 51J-4.
Note: The filters are not included. It was purchased new and never used.
A copy of the installation manual is included.
This is a rare find!