Northcore quad fin set * Set of 4 quad fins * Front: 4.5" * Rear: 3.5" * Material: Nylon * Compatible with injection-moulded FCS fins * Colour: Black The new Northcore FCS Compatible Quad Surfboard Fin Set is an injection-molded fin that combines a standard size of 4.5’’ front and 3.5" rear pairs. These quad fins are great all-round fins that are durable, strong, and perform brilliantly for an affordable price.