Slater Design Endorfins Twin + 2 Fin SetKelly Slaters twin fin template, packaged with two separate trailer options. The 11x World Champion on the Twin + 2 fin set: I started surfing on twin fins and obviously as surfing transitioned in the early 80s to thrusters, I went along with it. Over the years I have dabbled in twin fins, but only recently have I spent much time really refining board and fin designs for a performance twin. This fin design is what I settled on while wanting tight, in