I noticed that too when watching the film. I found a cheap one on Amazon under the title "Disguise Ghostbusters PKE Meter Accessory", which features two different pictures, that looks the same thickness as the PKE meter seen in the film. But it looks rather cheap. Technically, you could use the PKE meter from the GB:A toyline, but it seems rather smaller in comparison to the Spirit PKE Meter or even the Mattel PKE meter released years ago.