Each model measures the speed of bullets, arrows, shotguns, airgun pellets and paintballs, etc. - from 30/fps to 7000/fps and with better than 0.5% accuracy. It can go with you anywhere. Just unfold (like a book), mount on a tripod or place on a table, insert diffusers and shoot in less than 2 minutes. Each model is made of 20 gauge steel but weighs less than 2.5 lbs. It is powered by one 9-volt Alkaline battery (not included) and equipped with an extra large LCD readout (0.5" high). When folded, it is 7.5" long, 4.5" wide and 2.75" high. All Chrony's come with a 5 year limited warranty.