All of these chip stackers are awesome, but this one is EXTRA awesome with that sweet window to Kaj's soul in the middle of it! Inside this marble is ANOTHER slice of millie that you can only discover and view as you peek in thru that clear viewing window. Few things as great in life as marbles with secrets hidden inside!! Crazy hard to photograph of course, but leaves more mystery for you. It also has the UV core mystery going on, also hard to photograph, but crazy sweet in hand with that black light!! Luckily this one has some surface orange UV also, woohoo! Signed 'Kaj'.