Northcore quad fin set * Set of 4 quad fins * Front: 4.5" * Rear: 3.5" * Material: Nylon * Compatible with injection-moulded FCS fins * Colour: White The new Northcore FCS Compatible Quad Surfboard Fin Set includes injection-molded fins that are compatible with most FCS setup. These fins combine a standard size of 4.5" front setup and a 3.5" rear setup. Made of nylon material, these quad surfboard fins are reliable and durable with an all-around design.