You must hold it as you use, bps activates only when you shoot fast enough.
Well I needed a small portable chrono that was of good quality, but low cost. And for a while I could not find one of that discription. However, one day I was looking at paintballgears website and they had just got this new chrono in stock. So I checked it out, and with little to no reviews on the relatively new product, I took the chance and bought it for only $69. All I can say is that it was a purchase I do not regret since. This chrono filled most of my expectations. Especially its price, and quality ratio is excellent. It uses radar which makes its readings accurate and reliable. And rarely do you get a misread. The chrono fits in my gear bag since it is about the size of your hand. And it has 3 digit display which makes it much easier to read than the 2 digit yellow chrono everyone seems to be using. Also it comes with features that other chronos dont come with. Such as the ability to read in bps. However the feature only kicks in when it senses that you have fired at least a burst at around 4 bps or so. The chrono also takes very little power. I can take out a nearly used up nine volt battery from my loader or Ion, and put it in this chrono. Then use the remaining power on the chrono until the battery finally goes dead, saving me on batteries. Although too bad that it cant be hands free such as the yellow chrono, which can be annoying if you are trying to tune your gun by yourself and have to hold it too. It is a one button design that is easy to reset by just letting go, and pressing it again.
If you are looking for an accurate, convenient, reliable chrono to help you tune your gun, and to check if people are shooting hot, then this is the best one out there. Its portable size, and low power consumption makes this a very convenient part of a players gear.