Chuck Lightner (left), vice president, property development, Prudential Insurance Co. of America, points to the model of the proposed Andover, Mass. Tech Center, which is owned and developed by Prudential. With him (from left) are Andover town manager Ken Mahoney; state rep. Susan Tucker; U.S. congressmen Chet Atkins; and Gilbride McManus, president of R.M. Bradley Co., the executive leasing and management agent. Two of the seven 2-3 story office buildings have been completed. Buildings will range in size from 100,000 s/f to 130,000 s/f