The Shiny Object is an easy to use device that attaches to a threaded CO2 cartridge for the purpose of inflating a tire. The dial allows the user to control the amount of CO2 released instead of the all-or-none release of some similar units. It's small and easy to carry in a seat bag along with the CO2 cartridges instead of having to carry a pump along on the ride. There is no pressure gauge on the unit, however, so the user must estimate the desired pressure.
I have a Lezyne and Innovations valve inflators, but have replaced both with the PDW inflator. The PDW is the easiest, quickest, and fail-safe nozzle compared to the other 2. I inflate in 2 steps. At step 1, my PDW allows me to have very slow, controlled release (twist the valve knob) to minimally inflate the inner tube, but with enough air control to see the tire is properly seeded inside, around the rim. My Lezyne and Innovations is simple push, but each push comes in full bursts. I found these bursts are more difficult to control in my step 1. Step 2 is my more robust, but still controlled, release to reach my desired PSI. There are certainly experts using Lezyne and Innovations, but I'm not one of them. I don't flat that often. But, when I do, the PDW has ridden me of all my previous fumbling and frustrations I had with the other 2 brands.
When you need one of these you need it to work simply, reliably, and with some control. You get all of that with the PDW shiny object CO2 head. If you don't want to worry with carrying the little leather sleeve in your flat kit or saddle bag just use an old inner tube cut to length as a sleeve. This will keep you from freezing your hand. The dial allows you to control the flow of air so that you don't just blow the new tube or pinch flat straightaway. This is the standard for CO2 heads as far as I'm concerned. Get two!
This is the only valve I've ever used that actually holds pressure after it's pierced the C02 cylinder. I've used the partial pressure after a couple of months of initial use. I use it and several friends use them as well, all have had the same good luck with these valves.