This is a mint condition vintage 1969 resin display that contains a 1/6th section of a large heatshield bottom plug, that was used to cover over the bolts holding the heatshield to the Apollo 9 command module Gumdrop. The mission was flown by James McDivitt, Dave Scott and Rusty Schweickhart for the first flight in space of the Lunar Module. This resin was made by North American Aviation to give away to the astronauts, NAA and NASA management, workers and other VIP's.
The rule of thumb is that the larger the section of heatshield plug in the resin display, the more important the person. There were 10 full uncut plugs put in resin displays from most of the missions and they went to the most important people, followed by 1/2 cut plugs, 1/4 and 1/6 cut plugs, that were put into resin displays.