Advanced Drainage Systems is the world''s largest producer of corrugated HDPE pipe and related drainage products. ADS serves the storm and waste water industry through a global network of 56 domestic and international manufacturing plants and 27 distribution centers. In addition to its flagship N-12 pipe, the company offers a complete line of fittings and other accessories including, Nyloplast drainage structures and various geotextiles. Molded Adapter joins square downspout to 4 in. drainage pipe. HDPE material is strong, economical and resists rusting and corrosion. Snap joint fits inside 4 In. round pipe to create a tight fit.