Structural ribs inside prevent frost from adhering to the riser in the frost prone areas
Screw together assembly; Water and air tight
Lid, grate and basin sold separately
Made in the USA
6" Riser for 20" StormDrain Drain Box / Catch Basin Part No. FSD-3009 Dimensions: 22.8"l x 22.8"w x 7.3"h This distribution box riser combines all the best features of concrete and plastic risers to create our patented riser system. Features: -Hold their shape -Stackable -Screw together assembly -Water and air tight Structural ribs inside prevent frost from adhering to the riser in the frost prone areas.