The R200 can measure the dimensions of boxes, such as the height and width of cardboard boxes in a warehouse. You can find more information on box measurement with RealSense, including YouTube videos, by googling for 'realsense measure box'. The ZR300 has identical IR components to the R200, so should be able to similarly be used for this purpose.
You may also like to consider waiting a short time to see the specification of the new super-powerful RealSense D415 and D435 cameras coming in October, as they were designed with autonomous vehicles, drones and robotics in mind. The D-camera also have the ability to be synchronized with other hardware devices.
Click Store prices are in USD. I recommend this site for quick conversions to current CAD equivalents.
The R200 and SR300 are being retired very imminently and the standalone R200 is out of stock permanently. The only way to get an R200 developer kit camera now is as a bundle deal by buying the Robotic Development Kit, which contains the R300 and an Up Board single board computer.