Related to Ed's comment above about the index lines on the fin.... I have the WF mounted on a 2019 Radar 67" Senate Pro. I used the ski specific numbers on the Whisper fins site. Those numbers are..BF=30.75, Wing 8, FD 2.510, FL 5.570, DFT 1.95, LE 7.70. The front three index lines are exposed, the 3rd index line in the back is invisible. The ski is super reliable and easy thru 32off. However, the ski feels slow. My 35's are narrow and too much work and 38 is over at 1ball. I haven't tried the setup using the instructions that came with the ski. I defaulted to the ski specific setups. Any idea's to increase speed? I'm RFF, 205lbs and ski at 32mph. I will say that the first set was an absolute joy and there wasn't a scary moment . The fin felt great immediately! Of course, we always want more.