In 1968, Heuer redesigned the case used for the Autavia from a screw-back to a snap back compressor case.                               A compressor case was a patented case designed by Ervin Piquerez who sold these cases to a few watch manufactures, the compressor case has a unique seal construction which ensures water resistance through pressure on the gaskets and the crown. The principle is rather simple, deeper the watch was immersed, the more pressure on the case, the tighter the  case and more water resistant the watch.

However, despite the new case, the Autavia retained its original water resistance of 100 meters or 330 ft. the case was larger at 40mm.                                                                                                                                                                                                  There were a few (compressor case) Autavia references:                                                                             

Reference 2446C:  Black dial with 3 silver register fitted with Valjoux 72  movement.

Reference 7763C:   Black dial with 2 silver register fitted with Valjoux 7730 movement.                                                                   

Reference 7863C: Also known as "Autavia 30 Dato", black dial 3 silver register  with date fitted with Valjoux 7730 movement. 

Reference 2446C: GMT: Black dial with 3 silver subdial, with a red GMT hand, blue and red bezel with Valjoux 72-4. There are also different bezels : M (minutes), H (hours), MH (minute hour), T (tachymeter), P (diving), GMT.

This Autavia 30 Dato, which might be one of the rarest configuration of the compressor Autavia  is in excellent condition with sharp faceted case, the bezel has started to slightly turn grey.