Prosaunas selects the highest quality Alder with an attractive light color and a subtle grain pattern. Alder wood is durable and naturally water-resistant with a uniform pore structure and an even color consistency. Because of its low heat conductivity, Alder is a popular choice for sauna surfaces and will remain comfortable to the touch even in the extreme heat of a sauna. STP is an elegant profile that produces a refined and attractive wall surface for your sauna with its narrow grooves between broad cladding boards with rounded edges. It can be combined with other wood profiles for a contrasting appearance and to create your own unique, personalized look. Prosaunas carefully selects only the finest wood from Northern Europe and Canada, assuring that the quality and consistency of our wood selection is the best available. Our team has more than 55 years of experience crafting premium sauna rooms across North America, and we only offer wood that meets our stringent standards. Because of our total commitment to quality, we can ensure your wood order will arrive to your satisfaction. Wood Sizing - Nominal vs. Actual Lumber Sizes:In North America, wood sizes are given in"nominal"measurements, which is the lumber's size when it is cut from moist logs. After shrinkage from drying and surfacing, the actual size of lumber will be less than its nominal size. Please see the diagram for actual dimensions.