Hollis ST System BCD

Hollis ST System: Complete Backplate-and-Wing BCD Kit for Cold-Water and Technical Recreational Diving

The Hollis ST System is a factory-assembled backplate-and-wing setup that arrives ready to dive, with every major component already matched and integrated.

If you are moving away from a jacket-style BCD toward a proper plate-and-wing configuration, and you dive cold water, heavy steel cylinders, or both, this system is built around exactly those conditions.

What is in the box

This is not a wing alone or a backplate alone. The ST System ships as a complete, pre-assembled kit:

• ST35 Wing: 35 lb (16 kg) lift capacity, single-tank wing with a 360-degree tapered bladder profile
• Stainless Steel Backplate 2.0: AISI 304 stainless, 4 mm thick, laser-cut and CNC-bent
• Backplate Backpad 2.0: two-piece padded back cushion with lumbar support
• Solo Harness: one-size, trim-to-fit continuous webbing harness with stainless steel D-rings and cam buckle

The components are matched at the factory, so you are not hunting for compatibility between a wing from one brand and a plate from another.

The ST35 Wing: why the lift number and the shape both matter

35 lb of lift is meaningful if you dive a steel cylinder, wear a thick wetsuit or drysuit, or both. A standard single-tank recreational wing typically tops out around 25 to 30 lb. That extra headroom is not excess; cold-water divers with heavy exposure suits and dense steel tanks use it.

The bladder uses a 360-degree tapered profile, meaning the wing is shaped so lift concentrates toward your hips rather than sitting evenly behind your shoulders. In practice, this encourages a horizontal body position underwater, which is exactly what you want for efficient swimming and reduced drag. It still gives you enough surface buoyancy to float comfortably at the end of a dive.

The outer shell is 1680-denier Cordura nylon, which is a heavy-duty abrasion-resistant fabric. Inside sits a 420-denier nylon inner bladder that holds the gas independently of the outer shell. The two-layer construction means the outer shell takes the scrapes against rocks or the boat hull, while the bladder stays protected.

The inflator uses a K-style design with a crushproof rubber hose, and the elbow is offset to route the hose clear of your tank valve and regulator. The dump valve sits at the lower left, reachable when you are horizontal or head-down, which is the position you are actually in when you need to vent gas during a descent or while swimming.

One practical travel detail: the wing has cam band slots and a tank cradle built in. You do not need a separate single-tank adapter plate to mount a cylinder. That removes one accessory from your bag and one more thing that could go wrong.

The Stainless Steel Backplate 2.0

The plate is AISI 304 stainless steel at 4 mm thick, sandblasted and then electropolished and chemically passivated. Electropolishing smooths the surface at a microscopic level and improves corrosion resistance, which matters if you dive salt water regularly.

The 2.0 designation refers to a revised geometry with improved ergonomics compared to the previous Hollis plate. It is cut short enough to fit smaller-framed divers without the bottom edge digging in.

A stainless plate adds meaningful negative buoyancy, which is part of the point. Combined with a steel cylinder, it reduces the amount of lead you need to carry on a weight belt or integrated pockets, keeping your load closer to your center of mass.

The Solo Harness

The harness is a continuous one-piece webbing system, meaning there are no separate shoulder and waist straps joined by plastic hardware. Fewer connection points means fewer places for a buckle to crack or a joint to fail under load.

It is one size and trim-to-fit: you cut the webbing to your torso dimensions during initial setup. Once set, it fits your body specifically rather than adjusting loosely around you on every dive. The shoulder pads are removable and accept stainless steel D-rings, and additional stainless D-rings and a cam buckle are included.

The harness alone weighs 1 lb (0.45 kg), which is light for a webbing system of this construction.

The Backpad 2.0

The backpad is a two-piece design that adds lumbar support between you and the stainless plate. The two-piece construction lets each half pivot independently, which means you can swing the pad sections out of the way when you are mounting or removing a cylinder without fully disassembling the system.

One compatibility note worth knowing: the Backpad 2.0 does not fit older Hollis backplates. If you already own a first-generation Hollis plate, this pad will not work with it.

Who this system suits, and who it does not

The ST System makes the most sense if you are a diver making the transition to a backplate-and-wing setup for cold-water diving, heavier steel cylinders, or because you want a more streamlined, configurable platform than a jacket BCD provides.

The 35 lb wing gives you genuine lift margin for cold-water conditions. The stainless plate and Solo Harness are the same harness architecture used by technical divers, so the system has room to grow with your diving without needing to be replaced.

It is less suited to warm, tropical diving where you want to travel light. A stainless plate is heavier to pack than an aluminum one, and 35 lb of lift is more than you need when you are diving a thin wetsuit and an aluminum cylinder in the tropics. If that is your primary environment, a lighter wing and aluminum backplate would serve you better.

If you are a brand-new diver still learning buoyancy fundamentals, a plate-and-wing system of this type requires more initial setup and a different mental model than a jacket BCD. It is not the wrong choice, but it has a steeper setup curve and is less forgiving of an improperly trimmed harness.