From True Ames
Originally popular as glass-ons in the 1960's, now "D” fins sometimes need to be put in fin boxes. The larger area of the D-Fin fins allows for classic drop knee style turns and easy nose riding. Try one on your log and take a trip to the past.
The D-2 is 9.0” deep and has a 9.75” base. The D-Fins will just fit in the 10” standard fin box because we have made an overhang in the rear of the fin. You may have to take out your “fin box leg rope” but mostly we know D-fin riders do not use such newfangled attachments anyway.
own it from $10 a week with More info