Brake inspection plug time!
The inspection holes on your backing plates are sealed with rubber plugs.
This to avoid water and dirt coming in your brake system.
Up to 1968 model year they have been single plugs originally.
1969 and later cars had the "tandem" plugs.
These plugs have the same diameter, but are simply with two connected to each other.
These "tandem" plugs are new to the BBT program as from today.
Single plugs BBT # 1295 available
HERE