Van der Valk Rubber Elevation Block is made of recycled rubber granulate bonded with PU binding agent and possibly colouring. The black colour is not colourfast and there can be variations in colour as this is a recycled product. Suitable for ValkPro+ Roof. Carbon black is a black colouring present in every rubber tile which can exude under the influence of the weather. It has 5 years guarantee on the wear resistance of the product when used for a roof terrace, balcony and gallery.