Trick can also be done in reverse, and no need to use any sort of tube. This type of prop used to be used in tandem with another trick of the Coloring Book variety. Works similar to standard two color changing silks where you draw the two through your hand and they both change colors. So please don't perform this in the same dead giveaway manner. Can practically be waved through the air with a good snap and will visibly change. Might want to sew a tiny strong black thread loop inside to make grabbing the right place a bit easier. Might even be possible to tie one of these to a rod/pole to snap it in the air to change from black to rainbow. Just don't do it more than once and wear out the surprise and welcome. Kids will wow at the suddenly appearing colors, so use it in conjunction with a related trick and resist the temptation to change it back. No-frills construction, so decide for yourself if the price is appropriate. Sudden appearance of all those colors does look pretty cool when waved through the air horizontally.