Tough to tell 'em apart, but the two insulators on the left are CD 112.4s, and the one on the right is a 112.5. (That's a Hemingray 112.4 [010], a BTC Co. 112.4 [020], and a Diamond 112.5 [010]). Granted, the 112.5 is a bit shorter, but otherwise the profiles of the two on the right (112.4 and 112.5) look more alike than the profiles of the two on the left, which are both 112.4s. Unnecessary assignment of different CD numbers?