UNDERLIG foam mattress for junior bed white - IKEA
KRUMMELUR foam mattress for crib, 271/2x52" - IKEA
PELLEPLUTT Foam mattress for crib, 27 1/2x52" - IKEA
Bought a cot and mattress (Krummelur) from Ikea, but don't know which way is up for the mattress. One side is ribbed and the other is flat, so I assume orientation matters.