Read the owner's manual. Does that represent FPS or MPH? Were you flying a wingsuit, belly-flying, doing head-down, or what?
MPH. No suit. Started head down then belly
I don't understand your question then. If you know it represents mph, then why are you asking "what is that?" Do the speeds seem to match what you were doing on the dives? You can easily reach 151 and 171 mph while going head-down. What exactly are you unsure of?
I'm new and didn't think speeds that high could be reached