White plastic Z section profiles.  
Profile size is determined by the overall height of the profile marked H in the diagram.  W is half the size of H i.e. the 1.6mm profile has the following dimensions: 
H = 1.6mm, W = 0.8mm, T = 0.4mm, L = 250mm
Strong plastic, easy to cut, bond and build.  
Bulk quantity packs so you can save money on your larger projects.
Bulkscene product - registered trademark of Goodwood Scenics Ltd.