Both from IKEA... We have a Myrbacka and DS1 has a Morgedal. We love both.
DS1 has a mattress cover that we also got at IKEA. He wet through his pullup the other night and I was too tired to do anything other than changing him and throwing a towel over the wet spot. The sheet/mattress cover were still damp in the morning, but the mattress was dry and didn't smell.