Thanks, guys. I appreciate all the information.
I've also done some research on my own.
1. From Goodvac.com:
KIRBY VACUUM CLEANER INFLATOR/DEFLATOR TOOL
It is available only in 2 shades of light gray (Twilight) for Kirby Ultimate G and darker gray (Autumn Gray) for Kirby Sentria, since manufacturer has discontinued this part in other colors. Therefore, we are offering Inflator/Deflator only matching Kirby Sentria model color.
It WILL fit all Kirby sweeper "Generation" models (and even some older ones).
Generation 3 (G3)
Generation 4 (G4)
Generation 5 (G5)
Generation 6 (G6)
Ultimate G (G7 or UG)
Ultimate G Diamond Ed.(G7 or DE)
Sentria (G10)
Part #213806
2. From KirbyClassicIII (Ben)--"Kirby Attachment Box Arrangements Over the Years", Thread 20863, 5/22/2013:
(Looks like Alex is correct that the Inflator/Deflator began with the Kirby Classic III.)
http://www.vacuumland.org/cgi-bin/TD/TD-VIEWTHREAD.cgi?20863
3. Another from KirbyClassicIII (Ben)--"Using a Kirby to Clean Your Computer?" , Thread 16980, 5/18/2012:
http://www.vacuumland.org/cgi-bin/TD/TD-VIEWTHREAD.cgi?16980
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So, did other companies also make such a tool, or was Kirby the only one? Seems they've had the most exhaustive sets of attachments (at least that I've seen).