--- title: Zurn Z121-EB Roof Drain - Top-Set Adjustable Extension Assembly description: Find a product diagram and engineering specifications for the Zurn 121-EB roof drain with Top Set adjustable extension assembly. --- Search our inventory of drains, drain parts, safety and roofing equipment, and accessories. [Shop Now](https://hy-techroof.com/products/). - [ About ](https://www.hy-techroof.com/about-hy-tech/) - [ Contact ](https://www.hy-techroof.com/contact-hy-tech/) - - [![Hy-Tech Roof Products](https://resources.hy-techroof.com/hubfs/Logos/Hy-Tech%20Logo_rgb_maroon_480.png) ](https://www.hy-techroof.com) [**](https://www.hy-techroof.com/login.php) [**](https://www.hy-techroof.com/cart.php) ** ** [![Hy-Tech Roof Products](https://resources.hy-techroof.com/hubfs/Logos/Hy-Tech%20Logo_rgb_maroon_480.png) ](https://www.hy-techroof.com) [**](https://www.hy-techroof.com/cart.php) - - # Zurn Z121-EB Roof Drain - Top-Set Adjustable Extension Assembly *Dimensional data is subject to manufacturing tolerances and change without notice.*   ### **![Zurn Z121-EB Roof Drain - Top-Set Adjustable Extension Assembly ](https://resources.hy-techroof.com/hs-fs/hubfs/Zurn%20Z121-EB%20Roof%20Drain%20-%20Top-Set%20Adjustable%20Extension%20Assembly%20.jpeg?width=518&name=Zurn%20Z121-EB%20Roof%20Drain%20-%20Top-Set%20Adjustable%20Extension%20Assembly%20.jpeg)** **Specifications: **Zurn Z121-EB 12-in. roof drain includes a dura-coated cast iron (DCCI) body with combination membrane flashing clamp / gravel guard, Top-Set® adjustable extension assembly, and low-silhouette poly dome. | **Pipe Size (in.)** | **Approx Weight (lbs)** | **Dome Open Area (sq in.)** | | --- | --- | --- | | 2, 3, 4, 6 | 31 | 78 |   ### Outlet Types - Inside Caulk (IC) - Threaded (IP) - No-Hub (NH) - Neo-Loc (NL) ### Dome Options - Poly Dome* (4-1/4 in. height) with DCCI Body (Z) - Aluminum Dome (6-9/16 in. height) with DCCI Body (ZA) - Low Silhouette Cast Iron Dome (4-1/4 in. height) with DCCI Body (ZC) - Plain Bronze Dome (3-7/8 in. height) with DCCI Body (ZRB) **Regularly furnished unless otherwise specified.* ### Accessories - Acid Resistant Epoxy Coated Finish (-AR) - Neo-Loc Test Cap Gasket (2 - 4 in. NL Bottom Outlet Only) (-TC) - Bronze Mesh Screen Over Dome (-BS) - Vandal-Proof Secured Top (-VP) Deep Sump Body (-DB) - Vertical Expansion Joint (-XJ) - Static Extension (1 - 4-in.; specify height) (-E) - Stainless Steel Perforated Gravel Guard (-84) - Flush Grate (Replaces dome strainer) (-FG) - Stainless Steel Perforated Extension (-85) Galvanized Cast Iron (-G) - 2-in. High External Water Dam (-89) - Secondary Clamping Collar (-SC) - 90° Threaded Side Outlet Body (2 - 4-in. only) (-90) - Stainless Steel Mesh Screen Over Dome (-SS) [![image of blue zurn roof drain with text "zurn roof drains & replacement parts find and buy online"](https://no-cache.hubspot.com/cta/default/10783/dd59a7a6-a93c-475e-a021-79d328357d56.png)](https://cta-redirect.hubspot.com/cta/redirect/10783/dd59a7a6-a93c-475e-a021-79d328357d56) - [Drains](https://www.hy-techroof.com/products/drains/) - [Zurn](https://www.hy-techroof.com/manufacturers/zurn/) - [Smith](https://www.hy-techroof.com/manufacturers/j-r-smith/) - [Josam](https://www.hy-techroof.com/manufacturers/josam/) - [Wade](https://www.hy-techroof.com/manufacturers/wade/) - [Marathon](https://www.hy-techroof.com/manufacturers/marathon/) - [Olympic](https://www.hy-techroof.com/manufacturers/olympic/) - [Equipment](https://www.hy-techroof.com/products/equipment) - [Garlock](https://www.hy-techroof.com/manufacturers/garlock/) - [Leister](https://www.hy-techroof.com/manufacturers/leister/) - [All Seasons / Grizzly](https://www.hy-techroof.com/manufacturers/all-seasons-equipment/) - [Hennes-Johnson](https://www.hy-techroof.com/manufacturers/hennes-johnson/) - [Gator](https://www.hy-techroof.com/manufacturers/gator-roofing-equipment/) - [Roofmaster](https://www.hy-techroof.com/manufacturers/roofmaster-products-company/) - [Safety](https://www.hy-techroof.com/products/safety) - [Leading Edge](https://www.hy-techroof.com/manufacturers/leading-edge-safety/) - [Tie Down Manufacturing Ingenuity](https://www.hy-techroof.com/manufacturers/tie-down-manufacturing-ingenuity/) - [Malta Dynamics](https://www.hy-techroof.com/manufacturers/malta-dynamics/) - [Resources](https://resources.hy-techroof.com) - [Account](https://www.hy-techroof.com/login.php) - [The Drain Wizard](https://resources.hy-techroof.com/ask-the-drain-wizard) - [FAQ](https://resources.hy-techroof.com/faq) - [Blog](https://resources.hy-techroof.com/blog) - [Roof Drain Specs](https://resources.hy-techroof.com/roof-drain-specs-and-diagrams) - [Video Library](https://resources.hy-techroof.com/video-library) - [About](https://www.hy-techroof.com/about-hy-tech/) - [Contact Us](https://www.hy-techroof.com/contact-hy-tech/) - [About Hy-Tech](https://www.hy-techroof.com/about-hy-tech/) - [Service and Repairs](https://www.hy-techroof.com/service-and-repairs/) [800-635-0384](tel:8006350384) **Hy-Tech Products **10035 Broadview Road, Broadview Heights, OH 44147 [info@hy-techroof.com](mailto:info@hy-techroof.com) [800-635-0384](tel:8006350384) **Hy-Tech Products **10035 Broadview Road, Broadview Heights, OH 44147 [info@hy-techroof.com](mailto:info@hy-techroof.com) © 2026 Hy-Tech Products, Inc. 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