For a great space saving option to accommodate extra sleeping arrangements we recommend the pop-up trundle. This extra twin size mattress maximizes space in any room with a mattress that pops up next to the daybed turning this standard twin size daybed into a king size bed. For easy storage this trundle bed conveniently stows underneath the daybed when not in use. This wheels on this trundle do not lock. Please note that the twin size mattress used for this trundle bed is not included and will need to be purchase when checking out.