Ok, after diving with horsecollar bc's in the 70's, and jackets in the 80's, 90's, and 2000's, I packed away my last jacket, a Sherwood Avid, and now have a Hollis HD-100 back inflate. Yeah, I know it's not a BP and Wing, but for a crusty old diver, this is a drastic move. I made my first dives with it yesterday and today and all I can say is I should have switched a long time ago. It is the most comfortable bc I've had. The back inflate keeps me in perfect posture, head and chest slightly below horizontal. I was never able to achieve this with the jacket bc. I could never quite master the frog kick either but with the Hollis, it's a natural. There are a few things that I have to become accustom to. The Avid's inflator hose was also a dump valve. The Hollis is not. In order to dump air with the Hollis, you use either the right should dump or rear left hip dump. You can use the hose by pressing the dump button, but this will also allow water into the bladder. In order to dump air, you need to be in a fairly vertical position. Boyancy adjustment is so exact though, that I'm not making adjustments as often as before. On the surface, it supports well without throwing you forward. If anyone out there is looking for a bc that is back inflate with some tech features, check out the HD-100. Also, if anyone is interested in a Sherwood Avid, used but well maintained, send me a pm.