Habitrail Mini Outpost is a great add-on feature that your pet hamster will enjoy. It can be attached directly to the cage or to a Trail. Mini Outpost can be used as either an extra living space or filled with litter and used as a toilet. It also has a sliding door lock that keeps your pet safely in the cage when cleaning the base of the Outpost. You can also remove it and lock the door for short periods of time with your pet safely inside while you clean the cage. Mini Outpost comes complete with 1 cube, 2 lock connectors and 2 closure disks. Mini Outpost is compatible with both Habitrail classic and Habitrail OVO items.