original and intact early 20th century antique american industrial mahogany and pine wood steam trap valve cover two-piece interlocking foundry patterns salvaged from the boylston steam specialties co., chicago, il. manufacturer markings deeply embossed on the sides. patterns are wooden forms made to the exact specifications from which a mold is created from casting metal into. certain colors were used to signify certain specifications for casting purposes. yellow for example, identified areas of hollowness and were sometimes referred to as "core boxes." the unique american industrial pattern was manufactured for the boylston steam specialties co., chicago, il. hundreds of unique patterns were salvaged from the boylston factory. the pattern were used to fabricate cast iron "hoods" used on boylston "standard" steam traps.