[/QUOTE] That's because I find them reliable and I'm still alive to tell you that You absolutely must have a SPG (submersible pressure gauge) which you'll regularly be checking underwater to make sure that you've enough gas left I'd still go Apeks. The DS4's are actually Dry Sealed with 4 ports. This means that if you're swimming around in crap (mud, rust, sand, etc.) they don't get any inside. Scubapro Mk25s have holes in them to let the water pressure inside; not a fan of that. Scubapros also said to be more complex to service. On dive boats, particularly the technical ones, you'll see they're mostly Apeks. Simply that they're good value for money and reliable. Oh, and don't fall for the marketing BS. You don't need the greatest invention that's been pulled out of some designer's jacksie -- those crazy expensive Apeks new things are no different underwater than the DS4 & ATX40, except they're three times the price! Same for Scubapro. In fact buying those £300 regs mean you don't need to worry about them for a couple or three years. Second hand will normally need a service which will be circa £80 (which you need to factor in if you find a set).