Domino Detector magic

Description

Do you know the METAL DETECTOR??? I believe you do.  But have you ever seem a plastic domino detector???? Just imagine you ask four spectators to the stage and show them a black bag with four dominoes (1,2,3 and 4).  Draw in a blank paper a  Metal (no) Domino Detector (???). Yes, just a drawing. To prove that it works, ask them to reach inside the bag, and get any domino, do not look and hold it in a fist.  So that nobody knows which domino each one is holding.  Ask one of them to come close to  you, and scan your DOMINO DETECTOR over her hand. And tell exactly which domino she is holding. And repeat the same for every other spectator. You receive four dominoes (gimmmicked), and a marker (gimmicked), wireless chargers, black bag, All dominoes can be examined, or washed (solid resin molded). Of course, you can also perform the WHICH HAND magic, and tell not only which hand is holding the domino but also which number of domino is it (You have the  number 3 domino at the left hand !!!!.
You can see a simple demo on .....
https://youtu.be/13sKcVJLJus