What is it made of ?

Nothing fancy.

Only well known materials composed in an innovative way.

Plywood

Galvanized

steel profile

Cement bonded particleboard

Galvanized
steel profile.
DX51D-Z275
Class 1 Firerating

Cement bonded
particleboard.
CE-marked
PEFC-certified
Material class A
Cladding class 1
(K1 10 - B-s1,d0)

Plywood.
Pine and birchwood
CE-marked
FSC-certified
Material class B
Cladding class 2
(K1 10 - D-s2,d0)