Hi Doug, When I bought my M15 it had the original black plastic jam cleats for the jib halyards. They were the first things I changed on the boat. Reason: In the event of a sudden gust, I want to release the jib sheet instantly, and not have to wrestle with the jib sheet and the jam cleat to show who is stronger.............. .........and if I'm not.......? Then what? The boat gets laid on it's ear. I installed Rostan cam cleats, and now only have to jerk the jib sheet out of the cam cleat and my jib is free. I've had no difficulty with them since I installed them, but have not been in a reefed down situation with 20 - 25 knots of wind, though I have been hit with some fronts that made me glad I could free the jib instantly. They have been doing a fine job, and I'm happy with them. Connie