FCS II Harley Mid Tri-Quad Surfboard Fins - White/BlackHarley Ingleby's Mid 6 and Moe midlength models have become some of the most popular in this category. This is Harley's preferred fin set that's spec'd to work on longer boards and encourages a more progressive style of mid length surfing. HI also rides this set on in other hybrid shapes. The HI Mid set can be applied to any mid length with a Tri Quad setup. The set comprises the Reactor Large thruster template and the Performer Medium quad rear fins.