Karl_H
Contributor
Thats the Z-Plus harness with 50lbs of lift, it looks like the name has been changed to Z-Trim+. This harness isn't recommended as it is either too tight to use the lift or 'bubbles' in the centre if left too loose - it's a similar issue as the Razor BAT wing but the bubbling is worse in the Z-Plus, although the internal baffles help a lot in the Z-plus also.
The Alpha-Delta harness is similar but has grommets for mounting to a backplate, it has the same problems unless used with a back plate which isn't recommended unless you're diving backmount - a major advantage of sidemount is getting rid of the backplate afterall. The trim on this harness isn't great, it's workable but isn't the best unless you are diving dry, with a dry suit you can make it work a little better as it's easier to tweek trim with the suit.
The basic UTD Z-trim with 23lbs of lift is a nice product, it's great if you can make the lift work for you, otherwise I'd go with the stealth.
The z-manifold system has some advantages, okay maybe just 1 main advantage, but has a long long list of problems. I'd liken it to changing a steel wrench for a gelatine wrench as the steel one rusts, it solves the main problem at hand but introduces a lot of more serious problems. Basically the manifold is a solution to a problem that doesn't really exist, unless the original problem was making the equipment manufacturer more income.
I currently have three of the four harnesses mentioned above and previously owned the fourth (I swapped my Z-plus for an Alpha-Delta) and can safely say the harness that gets used the least by far is the Alpha Delta, most students try it once and move to another harness. A lot of people used the Alpha-Delta style of wing for technical courses before we had Stealth BCs available but it looks like it's now heading for retirement!
