TWP1500 Series is a low VOC formulation and should be used in place of TWP100 SERIES in low VOC states. TWP 1500 Series is an EPA registered wood preservative which prevents structural damage and wood decay on exterior above ground wood surfaces such as untreated or previously treated fencing, decking, wood siding, log homes and roofing.TWP 1500 Series is a low V.O.C. preservative with special U.V. protection. TWP 1500 series resists water absorption that causes warping, cracking and splitting as well as preventing freeze damage in colder climates. Designed for use on: Exterior new and old wood, Decking and fencing, Siding, log homes and more. EPA registered wood preservative. Premium semi transparent stain. Superior color retention. Prevents wood rot. Repels water longer. Easy to apply and maintain.