| 1 | ABT Inc. | | USA |
| 2 | C.I. Thornburg Co. Inc. | | USA |
| 3 | Kroy Industries Inc. | | USA |
| 4 | United Pipe Nipple Company | | USA |
| 5 | Springfield Plastics Inc. | | USA |
| 6 | Lane Enterprises Inc. | | USA |
| 7 | Atlas Tube Inc. | | USA |
| 8 | Spiratex Co. | | USA |
| 9 | ISCO Industries LLC | | USA |
| 10 | Ratnamani Inc. | | USA |
| 11 | StormTech Inc. | | USA |
| 12 | Pacific Plastics Inc. | | USA |
| 13 | Advanced Drainage Systems Inc. | | USA |
| 14 | Pittsburgh Corning Corporation | | USA |
| 15 | Conley Corp. | | USA |
| 16 | Insul-Tek Piping System Inc. | | USA |
| 17 | Urecon Systems Inc. | | USA |
| 18 | Century Industrial Supply Inc. | | USA |
| 19 | Environ Products Inc. | | USA |
| 20 | Fiskars Garden Tools Inc. | | USA |
| 21 | Snow Tech Snow | | USA |
| 22 | Comfort Brick & Tile Co. Inc. | | USA |
| 23 | Contech Engineered Solutions LLC | | USA |
| 24 | WL Plastics Corp. | | USA |
| 25 | Underground Devices Inc. | | USA |
| 26 | Asahi/America Inc. | | USA |
| 27 | Naylor Pipe Co. | | USA |
| 28 | Reliable Source Inc. | | USA |
| 29 | Marstan Inc. | | USA |
| 30 | Future Pipe Industries | | USA |
| 31 | Cal Pipe Industries | | USA |
| 32 | Valiant Steel | | USA |
| 33 | Arntzen Pipe | | USA |
| 34 | Town & Country Plastics Inc. | | USA |
| 35 | Uponor Inc. | | USA |
| 36 | Composites USA | | USA |
| 37 | Thermacor Process L.P. | | USA |
| 38 | Sewickley Construction Products Inc. | | USA |
| 39 | JM Eagle | | USA |
| 40 | Perma-Pipe Inc. | | USA |
| 41 | Argos Corp. | | USA |
| 42 | InfraPipe Solutions LTD | | USA |
| 43 | Dritherm International Inc. | | USA |
| 44 | Charlotte Pipe & Foundry Co. | | USA |
| 45 | DBJ Corporation | | USA |
| 46 | Sheet Metal Connectors | | USA |
| 47 | Pipefusion Services Inc. | | USA |
