So some deflators pull the valve stem out, others just push it in. I'm not a fan of removing valve stems so I got this. I've used it about 20 times. Depending on your initial air pressure and where you're going, I make a full adjustment (all the way in) on the 1st tire, less on the 2nd, less on the 3rd, then back to the 1st and check. That. When it reaches the desired weight I unscrew it completely and go to the 4th hoop with partial screwing in, then back to the 2nd hoop and it will be pretty close to the 1st in weight. And repeat for the 3rd and 4th hoop. You have to move, but it's very quick.