It has a single internal cavity 45mm wide running right around the box. It has rough walls and roof for bats to hang from. In both cases bats can move from one side of the box to the other without leaving the box.To securely install your Eco Rocket Bat Box usually requires around 1m of the pole to be buried below ground. Before erecting the pole however, we would advise you consult your builder or structural engineer as ground conditions vary from site to site. The Eco Rocket Bat Box comes with the option of a 4, 5 or 6 metre pole allowing you to select the length which best suits where it will be sited.For ease of installation and shipping, the pole will be dispatched separately from the bat box. Apart from erecting the pole, the only tool needed is a spanner to fix the box onto the pole.Features:Large self contained bat box including pole.Ideal solution in mitigation projects when no suitable building or tree is available on which to mount a bat box.Weatherproof recycled plastic outer shell protects a wooden roost chamber.Roosting area runs around the central pole allowing bats to move within the box to select their preferred micro-habitat.Available in two internal configurations for either crevice or cavity roosting bats.Comes as standard with a 4, 5 or 6 metre metal pole.Specifications:Materials: Box: Recycled LDPE plastic outer with internal OSB roosting chamberConstruction: Outer recycled plastic panels fitted together using integral tabbing system. Internal chamber formed from stapled panels.Crevice Internal: Divided parallel internal crevices 18mm wideCavity Internal: Internal chamber with no dividers 45mm wideDimensions and WeightDimensions (Box): Overall height: 860mm, Overall width: 250mm, Overall Depth: 240mmBox: 8 kg; Pole: 33kg (6 metre).