The detector was enormous for the early 1970's, weighing in at ~150 tons, with a length of 12 feet and a height of 20 feet. The colliding electron and positron beams were contained within a vacuum chamber of about 6 inches in diameter. The beam pipe was constructed from a very thin (0.008 inch) corrugated stainless steel tube. The two counter-rotating beams were collided at the center of the detector.