The main material of Haoxuan Wood Plastic Composite (WPC) Profiles are natural wood powder (about 60%),

by adding high density polyethylene plastic (about 30%) and necessary chemical additives.

It's extruded out from special moldings under high temperature and pressure.

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http://www.hosungwpc.com/html/en/products/hollowdecking/53.html Hollow WPC decking
http://www.hosungwpc.com/html/en/products/hollowdecking/52.html Hollow deck