I have the Antigravity Micro Start inflator
LINK $24.99 and works very well. They offer another version that comes with a SAE to SAE power cord for $5 more too. I just cut off the end of the cig plug power cord and put an SAE plug on myself, since my un-switched power on the bike is an SAE panel mount. This is the smallest, reasonably priced tire inflater I've seen.
I had been using a relatively small, ($10 on sale), Slime pump for years, which worked great too, but when I down sized bikes I wanted something smaller than what I was carrying in the Pannier. Previous bikes I had a WalMart $10 unit that I stripped out of the plastic case, trimmed off the fan blade and tied a leather boot lace to. That also worked great for literally years before I gave it to someone else after buying the Slime pump to fit into my nice square Zega Pro pannier on the S10.
I'm keeping it in a small MTM case under my license plate.
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