The Joma internal rear slot post box is lockable and has a mail slot on rear of box. Ideal for fitting on back of doors with an external mail slot to collect mail. Fittings included. The size of the mail post box is Size: 300 x 270 x 90mm (Mail Slot - 250 x 50mm). The Joma post box comes in a white finish. easylocks are the UKs main suppliers for Joma internal rear slot post boxes.