All 4" Internal Width Channels Polymer Concrete Home » Products » Trench Drains » Polymer Concrete » Polymer Concrete Channels » 4" Internal Width Channels Polymer Concrete T1500-PB-13 4″ Internal Width Polymer Concrete Channel with Galvanized Steel Edge Rail T1500-PB-3 4″ Internal Width Polymer Concrete Channel with Stainless Steel Edge Rail T1500-PB-4 4″ Internal Width Polymer Concrete Channel with Ductile Iron Rail T1560-PB-13 4″ Internal Width Polymer Concrete Channel with Galvanized Edge Rail T1560-PB-3 4″ Internal Width Polymer Concrete Channel with Stainless Steel Edge Rail