The Ball Fan is an easy to assemble desk fan. A simple 4.5V motor, 24mm in diameter, will fit snugly into the back cage, and can be bought from any electronics store. If you wish to create a custom base, the entire cage is 92mm in diameter. The design itself is Inspired by U-LIKE’s ‘USB Desktop Fan’, and 11+’s USB-powered ‘O-fan’. http://www.infmetry.com/products/u-like-usb-desktop-fan http://elevenpl.us/product/o-fan/