Air Systems Incorporated: Professional duct cleaning, furnace and flue vent cleaning. Commercial and residential services offered.Columbia Roofing, Inc.: Contractor for roofing, siding, windows and gutters.Conveyor Handling Company: Provides all aspects of material handling equipment and conveyor systems including design, installation, sales and service.Fresh Air Concepts - Residential and Commercial Heating, Air Conditioning, and Air Purification.: Commercial and residential heating, ventilation, air conditioning and air purification in Maryland, Lower Pennsylvania and the Washington DC Metro area. Products, services and company profile.Ingersoll-Rand Equipment Sales: Wholly owned subsidiary of the Ingersoll-Rand Construction Equipment Group. Full service facility serving the state of Maryland, Washington DC, and Northern Virginia.Maryland Shingle, Inc.: Full service roofing and siding contractor serving the greater Maryland area. Includes description of services, contact information and company background.Milby Company: Water system and monitor well products.Steven F. O'Donnell, Inc.: Sales and engineering arm for Wheeling Corrugating Company's floor and roof deck products.