The EGOI Portable Air Twin — 10.6 CFM, dual motor, with a digital control panel, hose, attachments and a storage bag.

Why this matters: dropping tire pressure on the trail lengthens the contact patch, which gives you traction in sand, rock and mud that no amount of throttle will. The catch is the other half — you have to put the air back before you touch pavement. Low pressure at highway speed builds heat, and heat is what destroys tires and unseats beads.

CFM is the number that matters, because it decides how long you stand at the trailhead. Taking four 35-inch tires from 15 psi back to 35 psi is a lot of air. A slow compressor turns that into a 25-minute job in the dark; a fast one turns it into a few minutes.

Two motors is what buys the speed. 10.6 CFM is enough to take a set of 35s from trail pressure back to highway pressure quickly enough that airing down stops feeling like a chore — which matters, because the people who skip airing down usually skip it because airing up is tedious.

It also has the output to run air tools and seat a stubborn bead, which a smaller compressor will not.

The digital control panel lets you set a target pressure and walk away rather than checking each tire by hand.

Portable, so it is not tied to one vehicle. If you would rather it lived permanently under the hood, look at the on-board EGOI system instead.