a > IT LLL Portland Grey Grate Removable snap-In grate il as Glass to 4" sewer pips REL Storm Drain™ Installation Instructions Concrete Finish refer note 4, 5 End Cop Install and seal either end of channel Channel Modular snap-together system Concrete Installation Concrete Top Course Compacted Sand, Cracker Dust, Road Base, Compacted Base Too ts 1 or Concrete refer note 2 refer note 1 Concrete Top Course Compacted Base .