Distributed by Winning Moves, purchased 2005,2007.
(plastic, same puzzle with different colors, 3.25 inches)

The two types of moves that can be made are to twist by 180 degrees along one of the three axes (having the effect of exchanging three top segments with three bottom segments), and to rotate the top and bottom with respect to each other by multiples of 60 degrees. This mechanism can be viewed as a generalization of Rubik's Cheese where the ability to rotate has been added.

McFarren's Page presents a solution that first solves the top and then the bottom. Jaap's Page also presents this approach, as well as one that starts by pairing up top and bottom segments.

The opposite sides of both versions shown above are black (the green/black is translucent):



Further reading:
Jaap's Page, from: http://www.jaapsch.net/puzzles/rubufo.htm
McFarren's Page, from: http://www.geocities.com/abcmcfarren/math/ufo/ufo1.htm
Rubiks.com booklet,, from: http://www.rubiks.com/World/Rubiks%20downloads.aspx