So for the longest time I thought every one's 'flush' buttons were broken (like the cracked in half). Come to find out, they are actually two different buttons all together. Who would have guessed? Obviously not this person. Well, the big button is for a big flush and the small one is for a small flush. I know, great logic. Or to be more scientific about it one is about 2.2 gal and the other just 1 gal. This system is know as the 'dual flush system'. I think this lands some where between America's system and Mexico's "if it's yellow let it mellow, if it's brown flush it down" system.