By the way, I bought five of the caps at HD this week for a friend that runs a bar. I had put a 528 in the 2-piece Gerber toilet after the Fluidmaster failed again from the 150 degree hot water that is plumbed to all of her fixtures (I know, I know...). It held up for 3 months, and then started running. Popped in one of the caps and voila -- good for another 3 months. Much easier than having the plumber come swap the valve. (I know...just connect the cold...I know. Let's just say it's the owners and leave it at that.) I left the others with her.

Just a point: Lowe's no longer stocks these (boo!!!!) while HD still does. I figured cleaning out the Manhattan HD of all of them might keep HD stocking them...