Super-O Power Buss Insulator No. 32-20 was available from 1957 until 1960, when it was replaced by the No. 32-45 which was available until 1966. There is no difference between these two inventory numbers except for the envelope in which they were packaged. One dozen of these came in each envelope.

These insulating connectors were used on the center rails to insulate block sections of Super-O track. While the insulating blade contents are common, it is the envelope that is collectable.

There are no variations.