whammy bar

[Drake Butler]

I have a Chinese made Ernie Ball (knockoff?) with no serial number. I'd like to attach a whammy bar but don't know the size. I receive one from Amazon that is 6mm and it is too small. Anyone know what size I should be looking for?

[beej]

With a counterfeit guitar, it's hard to say what size that would be. I'd measure the opening with calipers.