NDS 624 Green Plastic Spring Loaded Pop-Up Drainage Emitter with Elbow for 6" Pipes. Featuring a spring-loaded cap, it “pops up” to release water up to 88 GPM when pressure builds, and closes once flow diminishes. Cap stays closed when not in use to prevent debris & rodents from entering the drainage system. Weep hole on elbow drains water to prevent stagnation or freezing in cold weather. Flat profile design blends into the surrounding landscape. The Pop-Up Emitter with Elbow connects to 6 in. sewer and drain pipe; use included adapter to connect to 6 in. single-wall corrugated pipe. Cap, cover, and corrugated adapter made of high-density polyethylene (HDPE), elbow is made of polyvinyl chloride (PVC). Hassle-free limited lifetime warranty guarantees the NDS product is free from defects—or we’ll replace it.