This Collins Filter F 455 Y21 (part number 526-9337-00) is for the 32S-1 , KWM-2, and 75S-1 radios. It is in excellent condition and has a 2.1 KC band width. This one comes with the header for use in some other Collins receiver. It has been removed from a working radio and is in great shape. I am selling this filter as is as described.