The Carter AFB (Aluminum Four Barrel) was the second four barrel carburetor produced by Carter, after the WCFB. AFB's appeared in 1957 and were used as original equipment on most makes of car at one time or another up to 1971. The last notable automotive OEM application was as a dual-quad setup on 1971 Dodge 426 Hemi engines.
Interestingly, some Ford AFB's weren't made of aluminum at all, and were in fact cast out of zinc. Some of these appeared on Lincoln cars and marine applications.
Carter AFB's were produced as the Carter Performance Series carbs until 1998. Weber also produced marine AFB carbs; these were used as original equipment on large inboard marine engines into the 2000s.
They are currently available as Edelbrock AFB carbs, which are produced by Weber USA. Most parts, including tuning parts like the jets and metering rods are interchangeable between the original Carter AFB's and the currently produced Edelbrock carbs.
The Carter AVS (Air Valve Secondary) is a refinement of the basic AFB design. These can be recognized by the air valve above the secondary venturis. Information on the Carter AVS is here.