single c. 1920's antique american industrial refinished cast iron factory grease trap valve cover or hood fabricated by the boylston steam specialties co., chicago, il. the steam system component features prominent embossed lettering. the valve component contains two threaded steel pipes with flanges for supporting and/or displaying objects the hoods were originally used on the boylston "standard" steam traps. brushed metal finish was treated with a clear coat lacquer. similar valve covers available. measures 8 1/2 inches in diameter x 8 inches high.