Description Manuals Videos Articles Popular Accessories Poly Covers help keep contaminants from entering the blast machine. Moisture interferes with most blast media and cause blockages in the blast machine valves and plumbing. Poly, All-Weather, 45 x 68. Product Info Customers Also Viewed Clemco CPF 20 Breathing Air Filter System wit… #03578 $364.91 Clemco Exhaust Muffler, Complete #05068 $70.64 Clemco Heavy-Duty Blast Suit $233.61 - $333.37