A 40ft Platform doesn't have any walls or roof, and is appropriate for heavy machinery and other oversized loads.
The size of a 40ft PL is 12196mm x 2347mm (LxW).
A 40ft PL has a default tare of 5700kg and a maximum payload of 49000kg. Depending on your use case or specific container this might vary and is easy to change.
Every aspect of the container, from lengths to payload & tare, is of course customizable in Cargo-Planner.