Vernier Photogate (For LabQuest, LabPro, and CBL 2)... The Vernier Photogate works both as a traditional photogate for objects passing between the gate arms, and as a laser gate for objects passing outside of the gate. The gate has an input port so multiple gates can be connected in a daisy-chain configuration with up to four gates going to a single interface channel. The Vernier Photogate also supports auto-ID with compatible software. Photogates can be used to study free fall, air track collisions, pendulum periods, the speed of a rolling object, and many other things. The Vernier Photogate includes an accessory rod for mounting to a common ring stand. The laser gate mode requires the addition of a common pen laser, which is directed into the laser port. The laser may be some distance from the gate, so that you can measure the speed of larger objects such as a rocket, model car, or even a real automobile.