Secret Fix or hidden fixings, this is a closed construction providing hidden fix i.e. very few exposed fixings. This profile can be used for horizontal or vertical applications. We supply this profile in the SertiWOOD Viking Range painted cladding, Siberian Larch Tongue and Groove Viking, Siberian larch UTK Rhombus. The secret Fix profile should be screwed with minimum 4.5x40mm long screws.