bmx stem vs. mtn bike stem

[pnj]

what is the difference?

alot of them look almost the same.

i know that some of the mtn. bike stems are all light weight and stuff but can anyone give me a good reason to NOT use a bmx stem?

maybe the handlebars are a different thickness?

thanks!

[LostBoyScout]

BMX stems have a smaller handlebar diameter. (I believe)