A week before I left for the US, I picked up a puncture on my road bike after riding it on a road which had coarse gravel and salt strewn to combat the ice buildup.  The gravel often has very sharp pieces of stone which don't inconvenience cars, but can kill a road bike tire in no time, as I learned the hard way.  After fixing up the puncture, I started to inflate the tire with a new handpump equipped with a built in pressure guage.  Till I bought this pump, I had to manage with a small portable pump, which was quite difficult to use, and I'd go by the feel, for the amount of pressure.  This time around, instead of going by the feel,  I chose to trust the pressure gauge on the pump, and that was my mistake.  My bike's tire and tube were rated for upto 8.5 bar and I only wanted to pump up to 6 bar, but the guage under-reported the pressure by a big margin, which meant that my tire and tube simply blew up when the guage was still registering just under 6 bar.  When I was at the bike store in Livermore, I spotted the Topeak SmartGuage D2 digital pressure valve, and realized that it was exactly what I needed.

It has support for both Shrader and Presta valves and is very easy to use, and accurate. If done correctly, it only results in the loss of about 1 to 1.5 psi for the measurement itself. The gauge also has a 'tune' mode which can be used along with the air release button, to release excess air if any, while seeing the real-time pressure, to accurately drop down to the desired pressure level. It's capable of recording pressures up to 250 psi and also displays in psi, bar and kg/cm².

I put this gauge to use when I tried inflating the tires of my new fixie.  First, I pumped up using a portable bike pump by 'feel'.  When I thought it was good enough (the bike manufacturer recommends a minimum of 50 psi and a maximum not more than 85 psi), I checked with the Topeak.  Maybe as a result of the tire blowout experience, I found that I'd under-inflated it by a big margin! The tire was only pressurised to 29 psi.  I then pumped in some more incrementally, till I reached 60 psi, where I stopped.  Two thumbs up for this!