Building 4m x 50m 250mu Black PolytheneEmpak 4m x 50m 250mu Black Polythene Heavy duty 250mu Cost effective water proof membrane Composite resins with 5% carbon black Black Poly is extruded from a formulation of virgin polyethylene and reclaim resins at a 5% carbon loading. The carbon does provide limited U. V protection. It is commonly used as building film for damp proofing. Specifications Colour: Black Model Name: Black Polythene 4m x 50m 250mu Material: Composite Resins