Cold rolled steel parts for use in construction work, together with laminated plasterboard and gypsum board products where the frame is not load-bearing. U-shaped profile with unequal wings, which the T-45 profile slots into when pressed. It is part of the perimeter frame in self-supporting cladding panels and continuous ceilings that use T-45 profiles. It has a nominal width of 20 mm, with wings measuring 30 mm. It is made of 0.55-mm thick Z140 galvanised steel plate.