Auto & Tools

How we size up auto gear

For anything that inflates a tire, the numbers that matter are airflow (how fast it fills), duty cycle (how long it runs before it needs a cooldown) and power source — a 12V plug-in unit never runs out of battery but ties you to the car, while a cordless one works anywhere until the battery says otherwise. Max PSI matters far less than marketing suggests: almost every unit reaches car pressures; few move enough air for truck or RV tires.

For protection and emergency gear — covers, jump starters, TPMS — fit is the real spec: a cover sized wrong flaps in the wind, a jump starter under-rated for your engine won't crank it, and a trailer TPMS with short wireless range drops signal exactly when you need it. We flag those limits on each page instead of pretending one size fits all.