I have the White's machine with the 9.5 zero bouyant coil. I like the machine and have a good location to use the pi machine. What I dont like is the non open coil. It's hard to swing effectively for me in the water and wave action lifts it quite a bit. It's also heavy. I prefer the dd coil on my excal. Does anyone know if there is a different coil available for my White's either concentric or dd open style or even a spider style? Anyone on the forum making them? Thanx...Pete