Technical BCDs — Backplate, Wing, and Harness Systems

A jacket BCD wraps buoyancy around the torso and pushes a diver toward a vertical, head-up posture. Technical diving needs the opposite: buoyancy behind the diver, holding a flat horizontal position so the fins can execute a frog kick without stirring the bottom. That's what a backplate-and-wing does. A rigid plate carries the cylinders and provides ballast, a webbing harness holds the plate to the diver, and a separate wing bladder sits behind the back providing lift where it doesn't interfere with trim.

Separating those three functions is the entire point. Each component can be sized, replaced, or reconfigured independently — a steel plate for cold-water drysuit diving swapped for aluminium when travelling, a 30 lb single-tank wing swapped for a 60 lb doubles wing, a harness rebuilt from raw webbing at a fraction of the cost of a new BCD. Nothing is welded to anything else, and there's very little to fail that can't be fixed with a spare bolt and a webbing strap.

This collection covers complete systems, individual wings, harnesses, backplates, and sidemount rigs from Halcyon, Scubapro S-TEK, Hollis, OMS, Dive Rite, Mares, and Zeagle. At DiveCatalog.com, we carry these as an authorized dealer for every brand represented.

The Technical BCD Range

Complete Systems

The Halcyon Standard Single Tank System pairs a steel backplate with an Eclipse 30 lb wing and harness — a properly matched setup from a manufacturer that welds and tests every bladder in-house. The Scubapro S-TEK line offers Donut Wing configurations in 30, 40, and 60 lb paired with the S-TEK Pro Harness on stainless steel, with options adding a Single Tank Adapter and back/shoulder/waist padding.

OMS Stainless Steel Backplate systems arrive fully configured with Comfort Harness III or SmartStream harness, crotch strap, back pad with weight pockets, 6 lb weight system, and utility pocket. The Mares Tactical Green Single Backmount Set and Zeagle Express Tech Deluxe with inflator and hose round out the complete-system options.

Wings

The OMS Performance Mono Wing is a donut-style single-tank wing — the circular bladder lets air move freely side to side rather than trapping in corners, which keeps trim stable as you change orientation. The OMS Performance Double Wing and Deep Ocean Wing 2.0 extend the range for doubles and higher lift requirements.

The Hollis DT 50 lb Wing covers doubles configurations, while the Hollis CRIB Custom range includes ST 22 and ST 35 wings and a Katana 2 Single Wing for custom builds. Scubapro S-TEK Donut Wings are available in 30, 40, and 60 lb.

Harnesses

The Hollis Elite 2 Harness System works across tech and rec configurations and is sold without a backplate for divers building their own. The Hollis Solo Harness System takes the same approach. The OMS Comfort Harness III is available harness-only, and the Scubapro S-TEK Pro Harness is sold standalone for divers pairing it with an existing plate.

Backplates

The Hollis Stainless Steel Backplate 2.0 provides the rigid foundation and ballast. Steel plates typically add 5–6 lb of ballast, meaning that much less lead on your belt; aluminium plates weigh roughly 2 lb and suit travel and warm-water diving where you want minimal ballast.

Sidemount

The Hollis SMS Katana 2 is a dedicated sidemount BCD — a fundamentally different rig geometry, with cylinders carried at the diver's sides rather than on the back. Sidemount suits tight restrictions where a backmounted doubles set won't pass, and allows each cylinder to be removed and pushed ahead through a squeeze.

Travel and Modular Systems

The Hollis Elite ST and Elite ST Travel System address the weight problem in technical travel. The Hollis CRIB program allows genuinely custom builds — selecting wing, harness, backpad, shoulder pads, and LX2 weight system as individual components to spec a rig to your exact configuration.

Key Technical BCD Features

• Rear-only buoyancy: Lift behind the diver rather than wrapped around the torso, producing and holding a horizontal trim position rather than pushing you upright.
• Donut vs. horseshoe bladders: A donut bladder is continuous, so air migrates freely and can always be dumped from any orientation. A horseshoe design can trap gas in the wing tips when inverted.
• Steel vs. aluminium backplates: Steel adds roughly 5–6 lb of ballast, useful for drysuit and cold-water diving. Aluminium is around 2 lb, better for travel and warm water where you want less total weight.
• Continuous webbing harness: A single length of webbing through the plate with no quick-release buckles — nothing to fail, nothing to accidentally release, and rebuildable anywhere with basic hardware.
• Lift capacity matching: The wing needs enough lift to float your rig at the surface, and not much more. Excess lift creates drag and unnecessary bulk. Roughly 30 lb suits singles, 40–60 lb for doubles depending on cylinder material and exposure suit.
• Single tank adapter (STA): Lets a plate configured for doubles carry a single cylinder, so one rig covers both.
• Crotch strap: Prevents the plate riding up the back and provides a mounting point for a scooter or stage bottles.
• D-ring placement: Shoulder and hip D-rings positioned for clipping stage bottles, reels, lights, and SMBs where you can actually reach them.

Choosing Your Technical BCD

Maintenance & Care

• Rinse the wing inside and out — fill partially with fresh water through the inflator, agitate, and drain through the dump valve to flush salt from the bladder interior.
• Dry the bladder fully before storage, partially inflated, to prevent internal mildew and the inner surfaces sticking together.
• Inspect webbing for fraying, particularly where it passes through the plate slots and around D-rings.
• Check backplate bolts and wing nuts for corrosion and correct tension before each dive.
• Test inflator and dump valves for free operation and confirm the corrugated hose has no cracking at the flex points.
• Rinse stainless hardware thoroughly — stainless resists corrosion but does not prevent it, particularly in crevices.
• Store the wing loosely rather than tightly folded, which creases the bladder over time.

Why Buy Technical BCDs from DiveCatalog.com?

• Authorized dealer for Halcyon, Scubapro, Hollis, OMS, Dive Rite, Mares, and Zeagle — genuine products, full manufacturer warranty
• Complete systems and individual components — buy a matched rig or build it piece by piece
• Expert configuration advice — our team can help you match lift capacity, plate material, and harness sizing to your diving
• Fast shipping — in-stock items ship within one business day
• Financing available — for complete technical BCD systems
• Rewards program — earn points on every purchase

Frequently Asked Questions

Why use a backplate and wing instead of a jacket BCD?

Three reasons. Trim: rear-only buoyancy holds you horizontal instead of pushing you upright, which is what makes silt-free kicking possible. Modularity: every component can be replaced or reconfigured independently rather than replacing the whole BCD. Durability: a webbing harness and metal plate have almost nothing that can fail, and what can fail is field-repairable.

How much lift do I actually need?

Enough to float your fully-loaded rig at the surface, with modest margin — not more. Around 30 lb typically covers a single cylinder; doubles generally need 40–60 lb depending on whether cylinders are steel or aluminium and what exposure suit you dive. Oversizing a wing adds drag and bulk without benefit, and makes the rig harder to control.

Steel or aluminium backplate?

Steel adds roughly 5–6 lb of ballast, which is 5–6 lb you don't carry on a weight belt — the usual choice for drysuit and cold-water diving. Aluminium weighs around 2 lb and is preferred for travel and warm-water diving where you want to minimise both ballast and baggage weight. Many technical divers own both and swap depending on the trip.

What is a donut wing?

A wing with a continuous circular bladder, so air can migrate freely around the full loop. This means gas can always find its way to a dump valve regardless of your orientation. Horseshoe-shaped wings can trap air in the tips when a diver is inverted, making it harder to vent — which is why donut designs dominate technical diving.

Can I use a technical BCD for recreational diving?

Yes, and many divers do. A single-tank backplate-and-wing with an STA works perfectly well for recreational diving and gives better trim than most jacket BCDs. The trade-offs are travel weight with a steel plate, and a setup process that's less immediately intuitive than stepping into a jacket.

What is a Single Tank Adapter and do I need one?

An STA is a bracket that adapts a backplate configured for doubles to carry a single cylinder, providing correct spacing and cam band mounting. You need one if you're diving a single tank on a plate system. Several Scubapro S-TEK packages in this collection include one.

When should I consider sidemount instead of backmounted doubles?

Sidemount suits restrictions too tight for a backmounted doubles set, since cylinders can be unclipped and pushed ahead through a squeeze. It also reduces the load carried on your back between the water and the entry point, which matters on long walks to a cave entrance. It requires specific training and its own regulator configuration.

Browse the full technical BCD collection above, or narrow to Wings, Backplates, Harnesses, or Sidemount. Reach out if you'd like help speccing lift capacity, plate material, and harness sizing for your configuration.