Polk Pure Tech is the company name for Doug & Marilyn Polk’s affiliate site for GreenTech Environmental Inc., a Tennessee company. GreenTech products are space age devices that greatly increase purity of air and water in home and businesses. GreenTech products use nature's purifying power inside homes, schools, and businesses. See our products at GreenTechEnv.com, but call us for great rebates at 731-256-6604.