The E.R. doctor told me that they usually let you try to pass stones up to 6mm. My urologist is letting me try to pass one that is 6.4mm. With the trouble I'm having with mine, 7mm doesn't sound fun. I guess none of them are. I'm new to all this, so if anyone has better info, go with theirs.
By the way, 7mm is a half-way between 17/64 and 9/32 of an inch. A little bigger than 1/4 inch.
[This message has been edited by bayou_john (edited 10-03-2003).]