I carry my Milwaukee M12 inflator and with the 4Ah battery it works well for topping up if needed. It displays current pressure and has an auto cutoff at a set pressure so I just set it and walk away for a couple minutes. It was getting regular use when I had a screw in the tire tread and lost 5-10psi each day until I got that patched.
I have an extension with one of those 90 degree flip quick disconnects on the end of its hose and it takes a little finagling to get it on the inner dually. Once it's on it's solid and when you take it off by flicking the lever it just makes a pop and comes off without letting a ton of air out like the screw on ones.
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