Here’s a video of the Synchro Boxes magic trick by Tenyo, a Japanese company which creates puzzles, magic and novelty goods.
"Tenyo has received special permission from creator Bob Ostin to release his close-up magic masterpiece with a newly-designed gimmick that we developed. The more times you repeat this trick, the more baffling it becomes. Our new gimmick is cleverly hidden inside the construction of the boxes, so there is no need to hide anything in your hands, or remove at the end of the trick. The secret is extremely well camouflaged. You’ll be delightfully surprised at where we’ve hidden the gimmick. And your audiences will be astounded by this baffling magic."
The effect? It’s in Japanese, but it’s visual, so…watch Synchro Boxes>>