Channel Islands CI Tech 1 Medium- 5 Fin The legendary Al Merrick fin template by Channel Islands Surfboards. 4.50" (medium) fin size, designed with riders 165lbs and under in mind. Five fin set, designed to be ridden as a thruster or quad fin set-up. RTM - Tech 1 The Tech 1 honeycomb hexagonal core combined with teh Al Merrick template offers a medium flex pattern, making this fin a versatile option for a wide range of surfing abilities. Tech 1 is designed to perform in a variety of conditions and has a wide base for drive off of the bottom, more rake for big carves, and a finer tip for release off of the top. The signature CI smaller center fin frees up the tail. Futures ride # of 4.6, a balance between spring and control. Material: Polyester resin and fiberglass construction. Unique core reduces resin content and weight. Proprietary fiberglass weave and orientation is designed for maximum response and performance. Versatile high performance option. SIDE FINS: Depth: 4.52" Base: 4.50" Area: 14.99" ^2 Foil: Flat CENTER FIN: Depth: 4.36" Base: 4.49" Area: 14.63" ^2 Foil: 50/50