If you want to put it on the table or cabinet, no power supply cable, pls choose 30cm (rechargeable)
If you want to test the 3D effect by a low cost with a simple operation, pls choose the standalone version 42cm
If you like to use wifi(app) to control the fan by a low cost, pls choose the wifi version 42cm
If you want to use the fan to advertise in your own shop with the most cost-effective, pls choose 50cm.
If you are engineers or integrators, you want to install a larger image 3D video wall, pls choose 65cm.
If you are designers very care about the resolution, pls choose the highest resolution(1920*1080p) 70cm.
If you want to use it to do brand advertising, show a high-end image, pls choose the largest size 100cm.