Originally Posted by Cat Herder:
I have all metal, evacuation cribs, now. PNP's are no longer "recommended". They will net you a "Discussed proper, safe, infant sleep environments. Improvement plan recommended." statement on your public inspection record if you choose to keep using them.
So, even though legal, using PNP's make you look less than "Quality" on your public State inspection page. 
** Minimum 2 inch mattress required. 
The three inch mattresses compress to meet the minimum in under a year, so buying a 2 inch means replacing yearly. Yes, they come in with rulers. 
What state is that? CA?
ETA: I haven't seen that here yet, not that I'd be surprised to see rulers. My classroom got a violation on our last inspection for having some tape residue on the wall.