Voyager 2 holds the record for most celestial bodies observed in a single mission having flown by four planetary systems. Then of course Voyager 1 also became the first man-made interstellar object with Voyager 2 expected to do the same in 2016.
Stickers are circular and vinyl. Ideal for both indoor and outdoor use. Newer copies are now 3.5", but you can save by selecting older 3" copies.