The square post, a timeless style is expanded cellular PVC for quick and virtually maintenance-free! Classic craftsman series posts are not prone to the same environmental damage as real wood, such as splitting or cracking. Their E-Z Lock joints will not separate due to disproportionate changes in panel dimensions. When 2 coats of acrylic latex paint are applied, classic craftsman series posts will deliver years of service as promised against rot, corrosion, and moisture damage.