Wind-proof elastic hem Low cost protection from dirt, dust, moisture. Prevents contamination and evaporation. Heavy-duty elastic hem is securely lock-sewn, keeps cover in place yet allows easy removal when needed. Polyethylene Covers are made from clear 4 mil FDA-Approved LDPE, or 8 mil black woven LPDE (not FDA approved), with 3/8" wide elastic band. Anti-Static Polyethylene Covers are ideal for areas where flammable vapors are present.