Product details:
"The square post, a timeless style is in expanded cellular PVC for quick, easy assembly 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 by against rot, corrosion, and moisture damage.
