Roberts "The Black Thumb"Derived from the Black Diamond with the same nose outline and the addition of a pulled in round thumb tail. This board has single to double concave with an accelerated tail rocker. It excels in the upper reaches for wave size of a shortboard but you ride it 2 inches shorter, a half inch wider and in the same thickness. The shorter rail line allows for tighter arcing turns in the pocket. Designed for bigger surf, the Black Thumb is good wave board that