Star Trek: TNG Com Badge Sound Comparison & Battery Change Procedure
The one with the more accurate sound was manufactured by Kohn. It's 100% plastic. See the 90's commercial for the Generations magnetic com badge here:
https://www.youtube.com/watch?v=vj24kNJEQJs
The QVC/TV badges are one piece solid metal and beautifully polished. They feel like a piece of nice jewelry. They look the same as the plastic one, color wise, but they look brighter on camera because of the light, which doesn't seem to have the same effect on the plastic one. It's weird.
The magnets to fit the magnetic com badges (sometimes you get one where its fallen out), I got from apexmagnets.com:
3/8" x 1/8" Disc - Neodymium Magnet $11.99 USD for a stack of them. They n-48s IIRC, but I could have the number wrong. whatever's the one lower than N-52.