Nikon F2SA
AI version of the F2 Photomic is the F2A

AI version of the F2SB is the F2AS

But where is the AI version of the F2S ?

Here it is - F2 + DP-2A = F2SA.
The new F2SA next to the old F2S The DP-2A uses the DP-2 electronics and ring resistor, but uses the DP-11 prism and front mechanism
A DP-2 front plate and two DP-11 front plates were used to make the the DP-2A front plate