Flex Drain, Solid Black Polyethylene, 4-In. x 25-Ft.4" x 25', black, solid flex drain, expands from 6' to 25', can be used in most drainage applications, soil tight fittings are built into the pipe & the pipe holds its shape after it is bent, therefore no other connectors are needed, simply dig your trench, lay your flex drain pipe & cover it up, meets the corrugated polyethylene pipe association's test for crush resistance.