Perfectly rigid: can be used on a desk, in a cabinet etc. L-shape make for better support towards the rear. Practical: the grooves keep your documents better in place, round edges for easier handling. Can be installed side by side (thickness 5 cm or 10 cm) shock resistant polystyrene thickness 2 mm measurements of a kit of 6 modules: H 22 x W 30 x D 22 cm