Pacific Vibrations High -quality Fiberglass fins at an affordable cost MR'S famous twin template produces exceptional drive and speed. Lightweight Honeycomb Core fiberglass construction. The small stabilizer adds control while maintaining the freedom and maneuverability of a twin fin set up. Fcs Compatible Comes with fin key Front Fins Base: 5" Height: 5.5" Foil: Flat Rear Fin Base: 3.54" Height: 3.40" Foil: 50/50