The best piece of equipment for measuring vertical jump heights are mechanical testers. Studies show that when an athlete has a visual target they jump higher. Also, mechanical testers are very hard to "cheat." The only way for an athlete to cheat the tester is to not reach as high as they can when capturing the standing reach height. This is why almost all combines use mechanical testers.
The "standard" mechanical tester for over 40 years has been the Vertec. There are two options available; a floor stand system or a wall mounted system. The most common is the floor stand system.
The "NEW STANDARD" is the TH500 and TH1000 by The Top Hopper. This mechanical tester can be mounted anywhere, because the math is 100% built into the measuring device and independent from the mounting system. The Top Hopper vertical jump measuring systems are industrial grade and the most accurate tester on the market today.
Here is Side-by-Side Comparison
Floor Stand Systems
The Top Hopper vs Vertec
As you can easily see in the picture, the Vertec leans the higher it is raised due to the telescopic tube/floor stand. The Top Hopper has a rigid floor stand, which helps to deliver very accurate measurements