It features two cleaning modes – a 20 minute short cycle and a 40 minute long cycle with the latter using the entire tank to clean a space up to 300 square feet (the shorter cycle will clean smaller spaces up to 150 square feet). These cycles are time-based so the robot won’t stop when it senses a clean room as a Roomba would. There’s also a new handy info button on top, which provides basic info, as well as an LED status bar that shows the progress of the cleaning cycles. Like other models, the 450 won’t dock itself, recharge and won’t work on a schedule since it needs some sort of human interaction to fill the clean water tank and dispose of the dirty water. It’s now available for $600.