Here is a selection of new old stock 21.4 MHz center frequency Crystal Filters, new old stock, used in Watkins Johnson radios, made by various Mfg. You may choose from bandwidths of 10 KHz (WJ P/N 92001), [SOLD OUT 20 KHz],  50 KHz (WJ P/N 92000), 75 KHz (WJ P/N 92230). Physical size is the same for all as is the pin-out locations, size is approximately 1 inch wide by 2 3/8 inch long by 5/8 inch high. This size was popular in the 8617 series receivers. Buyer chooses the bandwidth unit wanted, at least 5 each are available and large quantites of 10. 50 and 75 KHz are on hand, so ask for quantities before paying for a large group! Check out my other items!  Be sure to add me to your favorites list!  I combine items for lower shipping.  YOU ARE BUYING ONE FOR THE PRICE-YOU PICK WHICH BANDWIDTH.