Factory constructed single units varying in length from 3.6m up to 18m, usually in 1.2m increments, and widths from 2.4m up to 3.6m. The major benefits to the client are speed of delivery and the ability to expand, reduce or relocate as requirements change. Externally the options are varied but the most popular are either economical texture paint or low maintenance Plastisol steel. Windows are normally UPVC double-glazed. Internally units are pre-wired and the layout and finishes can be as specific as the client requires and can include toilet and welfare facilities. The units arrive mounted on four telescopic adjustable jacklegs to take account of variations in ground conditions and provide easy installation. They are either available singly or in multiples and can be double stacked and accessed via steel stairways and walkways to provide accommodation that makes best use of the available space.