Wanted to try the Z-fins SL S- 38 from Andrea Rosati. All round this fin gives so much. Tried the 7.8 and 8.6 both with the PD 115 V5 and this fin. Both are a good combo. The fin never budges. Wind was not too much but that's where the fin really kicks in and gives you a nice speed and ability to power up over a broad spectrum. For me I have not bought this for end speed, but purely for the allround use.