Those types have a vinylPVC cover that is prone to tearing and can be slippery . They ' re only designed to be used with a fabric cover on top . Additionally , seams in the vinylPVC cover can trap icky fluids , etc . from blowouts and become stained over time . The Keekaroo is a solid material no seams or crevices to trap nasty stuff and doesn ' t need a cover of any kind . In the earliest days when my son would often pee during changes , I sometimes put a cloth diaper down to absorb the liquid but it was never necessary . Poop , urine , spitup none of it will discolor or soak in . Just a quick wipedown of the surface is all that is needed . It ' s also quite largelong which is excellent for olderbigger babies . My son is rather tall for his age and still fits great on the Keekaroo at 12 months .