Third Lung Second Stage Regulator Review: Fits Specific Scuba Diving Models

Third Lung Regulator Overview

Brownie’s Third Lung Second Stage Regulator provides breathing air for divers who require a replacement part for their specific equipment model.

A seamless breathing experience underwater depends on a regulator that integrates correctly with your existing scuba gear. The Brownie’s Third Lung Second Stage Regulator ensures this by serving as a direct replacement part for the Brownie’s Third Lung system.

This regulator provides a path to maintain your gear’s functionality without needing to replace the entire primary setup.

We evaluated 16 second stage regulators and selected 10 for this full review based on ratings and brand limits. This product was chosen because it had 1 buyer rating, the 8th most of the 16 screened, and is one of at most 2 per brand.

The Short Answer on the Third Lung Regulator

Best for: you need a specific replacement part that matches the Brownie’s Third Lung system for your existing setup.

The Third Lung Regulator is a practical choice for this specific replacement at $109.73.

• Pro: It is designed specifically for the Brownie’s Third Lung system.
• Pro: The price point is around $109.73 for a dedicated component.
• Con: The 5.0 rating is based on only 1 buyer, which provides no evidence of long-term reliability.

Don’t buy this if: your current regulator system is not a Brownie’s Third Lung model, as the compatibility is specific to that brand’s hardware.

Price assessment: The $109.73 price is a fair point for a specialized branded replacement part.

Specifications in Full

The 40 Inch hose length measures the physical distance of the tubing from the regulator to the connection point.

Before You Buy: Second Stage Regulator Checklist

The first thing to check is the specific model of your current scuba gear to ensure this replacement part is compatible with your existing setup.

• ✓ Confirm your specific gear model matches the Brownie’s Third Lung requirements — ordering the wrong part results in a component that cannot be installed and must be returned.
• ✓ Measure your current hose reach and compare it to the 40-inch hose length — a shorter hose than your current setup will limit your movement or require an additional extension.
• ✓ Verify your regulator’s connection interface is compatible with this second stage — a mismatch prevents the regulator from connecting to your cylinder supply.
• ✓ Check that your breathing requirements do not exceed the flow capacity of a standard second stage — high breathing resistance can lead to CO2 buildup and exhaustion.
• ✓ Ensure your setup does not require a specialized technical or sidemount configuration — this product is designed for standard recreational use and may not fit specialized layouts.

You should not buy this product if your specific diving configuration requires a specialized high-end engineering benchmark like the Apeks XTX or Scubapro S620 Ti.

What These Specifications Let You Do

How to verify this Second Stage Regulator fits your scuba model

You need to confirm your specific scuba regulator model before purchasing this component to ensure a proper fit. The Third Lung Regulator is designed to fit specific models, so you should enter your model number into the manufacturer’s compatibility tool to verify the connection.

Verifying the correct model prevents the risk of purchasing a part that cannot be physically attached to your existing gear. Since the data does not state a specific list of compatible models, confirming your model number is the only way to ensure the Third Lung Regulator integrates with your current setup.

Using this Second Stage Regulator as a replacement part for gear

Replacing a worn second stage involves swapping out components to restore consistent breathing performance. The Third Lung Regulator serves as a replacement part, allowing you to maintain your gear without replacing the entire assembly.

The Third Lung Regulator features a 40-inch hose length, which determines the physical reach of the tubing from the first stage to your mouthpiece. This length dictates how much slack you have for hose routing and positioning during a dive, providing the specific reach required for your configuration.

The Third Lung Regulator Against Similar Second Stage Regulators

The Third Lung Regulator offers a 40-inch hose length, which is the longest measurement among the options we compared.

• The Rego LV4403B46R Low Pressure Second Stage Regulator is $0.22 more expensive than this model.
• The Rego LV4403B4 Low Pressure Second Stage Regulator is $3.93 cheaper than the Third Lung Regulator.
• The SEAC X100 Octopus Second Stage Regulator is $7.24 cheaper than this model.
• The Hollis 100LX Second Stage Regulator is $10.22 more expensive than the Third Lung Regulator.
• The Sea Elite Scout Compact Octopus is $20.22 more expensive than this model.
• The Third Lung Regulator ranks 1st highest-rated of 4 in this comparison, though the 5.0 average comes from only 1 buyer rating.

If you need the lowest price point for a second stage regulator, the SEAC X100 Octopus Second Stage Regulator is the more economical choice.

If you are considering different brands, see our full Oceanic Alpha 10 review for a detailed performance breakdown.

For a different style of breathing, look at our full review of the Delta 5 Regulator.

Setting Up This Second Stage Regulator, and What Support Covers

Setting Up Your Third Lung Regulator

You must have a compatible scuba regulator first stage to connect the Third Lung Regulator before it can provide air.

1. Unpack the Third Lung Regulator and inspect the housing for any visible defects.
2. Identify the connection type on your first stage to ensure it matches the Regulator Hose.
3. Attach the Regulator Hose to the first stage and the Third Lung Regulator.
4. Install Replacement O-rings to ensure airtight seals and prevent leaks at the connection points.
5. Connect a Submersible Pressure Gauge to monitor cylinder pressure during the dive.

Warranty and Support: What to Check

Warranty coverage and return policies differ by seller and country.

• Confirm the connection type of the Regulator Hose matches your first stage to avoid a non-functional setup.
• Verify the integrity of the Replacement O-rings to prevent moisture accumulation or leaks.
• Check the Submersible Pressure Gauge for accurate readings to ensure you can monitor your air supply.

Test the regulator for consistent breathing resistance by performing a dry check as soon as it arrives while the return window remains open.

Third Lung Regulator Buying Questions Answered

How the $109.73 price point affects compatibility and value

Ordering a second stage regulator that does not match your specific scuba system can result in a non-functional setup and the cost of a return. The Brownie’s Third Lung Regulator is a budget-friendly replacement option at the $109.73 price point. This price point provides a lower-cost entry for those seeking a basic replacement compared to high-end engineering benchmarks like the Apeks XTX or Scubapro S620 Ti. While the 5.0 rating comes from 1 buyer rating, this small sample size provides no data on the long-term reliability of the unit.

Is the Brownie’s Third Lung Second Stage Regulator the best value for a basic replacement?

The Brownie’s Third Lung Second Stage Regulator offers a low-cost solution for a basic replacement at around $109.73. Because the price is significantly lower than high-end benchmark models, it serves as a budget-conscious choice for divers who do not require the specific engineering of premium brands. However, because the 5.0 rating is based on only 1 buyer rating, the data does not confirm its long-term performance or value over time.

Budget-conscious setups can find the best second stage regulator for backmount under $150 in our comparison.

To understand the hardware better, look at the different types of second stage regulators explained.

Is the Third Lung Regulator Right for You?

Who the Third Lung Regulator suits and the jobs it is the wrong choice for, listed below with the reason for each.

Where to Buy This Second Stage Regulator

When we looked in November 2026, the Third Lung Regulator was listed at $109.73 – a snapshot that may have changed since.

Second stage regulators are sold by the retailers below – we do not track which of them has the Third Lung Regulator in stock, so check availability and the current price with the retailer before making a trip.

• Amazon (online only) — broad availability of entry-level and consumer brands
• Dick’s Sporting Goods (online and physical stores) — physical locations for immediate pickup of common brands
• ScubaGear.com (online only) — wide selection of major brands and technical gear
• DiveInn (online only) — extensive inventory of international scuba brands
• Triton Diving (online and physical stores) — specialist staff and local equipment servicing
• Scubapro (online and physical stores) — official manufacturer outlet for brand-specific parts and gear

Divers interested in specific setups should see the best second stage regulator for hookah diving selection.

Final Verdict on the Third Lung Regulator

This model is available for approximately $109.73.

The Third Lung Regulator holds a 5.0 rating from 1 buyer, though such a small sample size provides no data on long-term reliability or performance. The 40-inch hose length provides a specific reach for your configuration, which is the primary dimension for this part.

Skip it if: You need a regulator with a different hose length than 40 inches or require a product with a larger volume of verified user reviews.