White plastic deep U channel profiles.  
H and W equal the same dimension.  I.e. 1.6mm U channel is 1.6mm wide by 1.6mm high. 
The thickness (T) is approximately 0.5mm for the small sections and 1mm for the larger sizes (4.8mm and larger).  
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.