Spin Cycle is a simple device that allows you to spin a mapped dial/fader by pressing a button. When you first press the Spin button, it will spin the dial up to the maximum you've specified. When you press it again, it will spin it back down. If you press the Spin button while it is spinning, it will pause the spin and a second press will resume the spin.
You can specify max, min, and curve values along with the duration the full spin will take. You can also change the direction of the spin. The CF button automatically maps Live's crossfader to Spin Cycle. It seems that the crossfader isn't mappable to Max For Live devices in Live 8.3.4 (maybe a bug?), so this button works around that.
Available at MaxForLive.com: https://www.maxforlive.com/library/device/1449/spin-cycle