History
J.B. Desalvio was a casino gambler who cheated at the roulette table using a miniature magnetic device in his pocket. Winning several times in a row caused Janet van Dyne, who was patronizing the same casino, to become suspicious, and she asked her beau Hank Pym to investigate. As soon as Ant-Man discovered the trick, his ants removed the mechanism, thus ending his six times in a row winning record[1].
Paraphernalia
Equipment
A pocket-sized magnetic device that he could use to fix what number roulette wheels landed on; if it could affect other gambling machines or had other uses was unrevealed.