This is a replacement set.
One (1) center fin. Screw in.
Two (2) smaller fins. Screw in.
The fins are black, in like-new condition.
The smaller fins are 4" tall. The base is 5.5" long, and 3/4" wide. It is approximately 5 mm thick (not 4 mm thick, like the other style).
The center fin is 10" tall. The base is about 6 3/4". It is approximately 5mm thick.