After reading a wanted post from TLea on a Bendix 68 version of the clamp style booster, I wondered how many other versions there were. What application was the 68 clamp style (midland) Bendix booster used for? All the originals I have owned had no markings except for the tag attached at the band screw. The NOS units that I have had over the years were the updated red dot version and most had the Ford script etched on the case. While on the subject are there any differences on the check valve?