This is a pair of excellent quality new Lucas Fogranger back-mount foglamps. They are about six inches in diameter and use British prefocus (BPF) bulbs, as original. They come with clear tungsten bulbs; yellow bulbs are available for $30/pair (shown in the picture) and halogen bulbs are available for $20/pair for brighter light output.
These back-mounted foglamps were originally fitted to Jaguar Mark 2 (or MK II), 240 and 340, Daimler 2 1/2 and 250 cars, and some Vanden Plas Princess models. US-market models and some 240 and 340 cars did not come with them, but had fake horn grilles instead. These lamps are an excellent upgrade for cars not equipped originally with foglamps, or perfect replacements if your old ones are shabby.
We also stock the embellishers or "pie plates" that mount behind the lamps for $25 apiece.
We occasionally get new old stock lamps from England, although these are becoming VERY hard to find and are quite expensive. Contact us for prices and availability. As of October, 2015, we do have two pairs of NOS back-mount Fograngers in stock.
For the finishing touch on your Mark 2 or S-Type Jaguar, we often have original 4-position lighting switches (in good secondhand condition), complete with escutcheon that reads "O-S-H-F" (Off, Side, Head, Foglamps), for $85, here https://jollyrogersmotors.com/store/p/853-Headlamp-Switch-4-position-Jaguar-Mark-2-Original.html.