47x175mm is also commonly known as 7×2 inch, although the actual finished dimensions for this product are 45x170mm.
This is because it has been machine regularised which means the faces and edges have been slightly smoothed down and the corners slightly rounded or eased, the result of this process means the timber is smoother, straighter and easier to handle.
The treatment is green pressure treatment, which protects against rot and insect attack, UC3 graded for outdoor use.