Day & Zimmermann is a century-old, family-owned company whose 23,000 employees specialize in construction & engineering, staffing and defense solutions for leading corporations and governments around the world. Operating from more than 150 worldwide locations with 2.5 Billion USD in revenue, Day & Zimmermann is currently ranked as one of the largest private companies in the U.S. by Forbes. Founded in 1901 and headquartered in Philadelphia, PA, our first work was to develop "Betterment Reports" that helped modernize American factories. Today, we are still in the business of betterment -- maintaining the nation's power infrastructure, protecting American freedoms and driving technological advancements around the world. We do what we say.® http://www.dayzim.com