i had a 8mm in, biggest i'd have gone. but when i was on a fair ride at reading fest, it got ripped out and went all bloody :( then the next day it had scabbed shut - lovely, i know.
this was mine:
http://a7.sphotos.ak.fbcdn.net/hphot..._8283509_n.jpg
whoever it was who mentions 'bars', if you ment scaffolds then i got one. they're amaaaazing.
edit: here's a pic of the scaffold, it's a bright pic but you can still see it.
http://a1.sphotos.ak.fbcdn.net/hphot..._2544559_n.jpg

