standards are great!
my toilet had a leaky gasket and I was ordering the part to be delivered, and my local hardware store had it in two standard sizes, 2" and 3".
I was uninterested in taking apart my toilet again to measure it, and I needed to make up a minimum order amount anyway, so I just bought both sizes!
anyway my toilet is a 3rd size unknown to man or god, because fuck you and fuck your standards