These Royal Air Force 5 inch Wide Field aerial lenses are somewhat common.
I honestly don't know much about them. Supposedly Ross WA Xpres?? f4 - f16
Poor man's wide angle. $44
Next is an obscure little Wolly Anastigmat f6.3.
It is 5 inch focal. Covers 4X5. Cute little thing. I could probably throw the lens away and get more for the sweet little Betax No. 2 shutter.
$77 + shipping.USD
Price : 77.00