P-322 Edison DD Half-length Main Spring: 1-1/2″ wide, .028″ thick, center arbor ⅝”, both “hole” ends, in 2-1/2″ coil, and is about 12 feet long. This appears to be an original old stock spring, the inner half of an Edison Diamond Disc main spring (possibly salvaged from a full main spring) to be connected by riveting with an outer half – if one has a good outer half. This is not an easy project! Please note: Springs are NOT returnable. Extreme caution must be used when working with mainsprings! Not responsible for damages or accidents!