talkmagic.co.uk

can you do this with any bottle and cap
or just one kind?
like one brand

Although this, in theory can be done with any kind of bottle and cap, there is some set up required and of course the gimmick. Also, it's not examinable unless you remove the gimmick before handing out the bottle which COULD be a little awkeward to do invisibly.

I'm sure that this was reviewed somewhere but I can't find it either.

Personally, I wasn't too impressed and though that the cost was rather a lot for the gimmick. This may not suit everyone's style of performance.