400P-RV Automatic offers automatic shut-off in a larger portable compressor kit that can inflate 35-inch tires from 0 to 30 PSI in less than 5 minutes. While the unit is intended for RV use, it can be used for virtually any tire since it comes with more accessories for more varied inflating situations than any other portable compressor kit on the market today. Portable compressors with automatic shutoff come into play when moving from tire to tire, and when checking tire pressure in the middle of a tire fill. A typical portable compressor must be turned off between tire fills, and anytime you want to check tire pressure. If you aren't near the compressor, this can turn into running laps back and forth to the portable compressor to turn the unit on and off. Automatic portables do not work in this fashion and will save you time & effort to get tires inflated quickly.