Okay, edited the photo, but it is not verticals. Sorry.

Aerospace Vehicles Incorperated bought or assumed the rocketry side from MPC. I had previously helped certify motors from MPC with Myke Bergenske. In addition to the motors from the MPC days, AVI established a line of Gold motors, many of which were aimed at competition.
They claimed increased accuracy in designation and delays. Unless they were outside a set designation the NAR Standards and Testing allowed the manufacturer to market motors as claimed (most manufactures set their other motors the same as established brands like Estes and Centuri to gain equivalency and avoid confusion. Only the thrust-time curves - subject to change with propellant supplies - told the true story).

AVI Astroport 18mm D6.1-3.25 and 6.75 from 1975. Subject to casing burn through due to longer burn time. 24mm E11.8-9.75 and -7.50 from 1978. My favorite was the -4.25 second delay in my Estes Maxi-Brute Honest Jofn with the FSI 27mm motor mount. But I digress.
33mm F23-6.50 from 1978.
Tiny competition motors of 6mm if I recall correctly. 1/4A1.7-4.00 and 1/2A1.5-3, both from 1975.

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__________________
Charles Russell, MSgt,USAF (ret.)
NAR 9790, Lvl 1
SAM "Balls Three"