Thats because the US Navy has two rear admiral ranks. The lower rear admiral is a 1 star officer and is equivalent to commodores in other navys. The upper rear

Thats because the US Navy has two rear admiral ranks. The lower rear admiral is a 1 star officer and is equivalent to commodores in other navys. The upper rear admiral is a 2 star officer is equivalent to "normal" rear admirals in most other navies.