P-321 Main Spring for EDISON DIAMOND DISC Motor. The spring is NEW, identical in size to the original (1 1/2 inches wide with 5/8 inch center, and 0-0 ends, 25 feet long.) This is always a very challenging and dangerous installation. At over 80 years of age, I cannot install these springs any more. Please note: Springs are NOT returnable. Extreme caution must be used when working with mainsprings! NOT RESPONSIBLE for damages or accidents! [Be sure of the direction the spring must be inside the spring barrel.] HINT: Recommended booklets: L-103 and L-164 for additional information, while available.