M SORA and SILVAPRODUKT, two Slovenian SMEs dedicated to wood products and wood preservation present WINTHERWAX, a passive window made out of Norway spruce (Picea alba). It’s thermally treated wood is processed through the unique SILVAPRO patented process, and coated with an innovative preservative wax. The result is a wooden passive window cost-effective (the window will be sold at a price of 3 ...