RaceQuip window nets are constructed of heavy-duty 1" polypropylene webbing and nylon thread for maximum durability. RaceQuip utilizes a jig-built construction technique to ensure consistent size, shape, and fit. This auto racing window net fits a window size of 18" high x 24" wide which is standard and will fit most common racecar window openings. SFI 27.1 homologated.