The image below shows one of the large crates that Game Mat EU retails from their website. It is made of a type of resin that is heavier than the standard Forge World stuff. It also needs washing though, so make sure to undertake that step. The interior of the crate is also hollow. When I was washing mine, the inside started leaking ever so slightly and I wound up with water trapped inside the crate for days on end as I waited for it to dry through some small cracks in the (otherwise thick) resin shell.
For painting, I sprayed on a black undercoat and then followed this up with a mechrite red base coat all over. The metallic hoops around the crate were picked out in gold and then everything had an extensive black wash. I then picked out some limited highlights before going to town on the scratches on the surface and the rusting (mostly a creamy orange colour). The overall effect is of a worn crate that has long since seen better days. On the battlefield, it will provide solid cover and block lines of sight. The height of this crate is more than double a regular space marine for scale comparison purposes. Looking forward to using this in our games tomorrow.