KELLER & MARQUART AG ni mtoa ya bidhaa na huduma kama vile dirisha uingizaji hewa mifumo, plastiki, watazamaji tu,milango, patio, plastiki,madirisha, plastiki, pande zote,madirisha, bull's-jicho, plastiki,madirisha, hothouse, na ukaushaji lisilovunjika plastiki,paa taa, domes, plastiki,majengo, yametungwa.