Duh! Read questions and answers.. bottom trundle only fits a bunkbed thin mattress. I didn’t read this first and messed up my plan. Also you can put a thicker mattress on top one but then you lose back and side which holds up your pillows and makes it feel like a couch. But we still like it. Once you add in price of mattresses almost would’ve made sense to just buy the cooler pullout futon bed things which are a little more pricey. Oh well, still happy with purchase