Review on Unique Cash Challenge for Grown-Ups by Abhinav Drury

It seems like a cool thing and there were a lot of positive reviews. However, there are NO instructions for it. Bought 6 and had to send them back. There is only one notice on the packaging (labeled "on" and "off" which doesn't help much, especially since it's not even marked on the device itself. It seems like a silly oversight. I wanted them Sending children who in some cases don't have a computer to look for solutions on YouTube can't figure out why they did this.Otherwise the product seems to be of good quality and unfortunately I have to return it.If you have a super puzzle -Man are that can not bother you.