Transfill Hoses

Scuba Transfill Hoses for Diving Cylinders

Scuba transfill hoses, also commonly referred to as decanting hoses, are high-pressure hose assemblies designed to safely transfer breathing gas between scuba cylinders. They are primarily used by dive centres, technical divers, instructors, gas blenders and qualified technicians during cylinder filling, pressure equalisation and breathing gas preparation.

Whether you need to equalise pressure between cylinders, assemble a professional gas transfer system or replace worn components, this category includes a complete selection of scuba transfill hoses, complete gas transfer kits, fittings, adapters and replacement parts for professional applications.

Our range includes equipment compatible with DIN 200 bar, DIN 300 bar and INT/Yoke connections, suitable for compressed air, Nitrox, Trimix and oxygen service, depending on the specific product and its intended application.

Choosing the correct transfill hose depends on the cylinder valve connection, operating pressure, breathing gas and intended use. For this reason, we have organised the category into dedicated sections covering complete transfill hoses as well as fittings and replacement components.

What Is a Scuba Transfill Hose?

A scuba transfill hose is a specialised high-pressure hose assembly designed to transfer breathing gas safely from one scuba cylinder to another.

Unlike standard HP hoses used to connect pressure gauges, transfill hoses are specifically engineered to allow controlled gas transfer through dedicated valves and fittings capable of operating at cylinder pressure.

These systems are intended exclusively for surface operations and must never be used underwater. Their use requires suitable equipment, proper training and compliance with recognised safety procedures.

When Are Transfill Hoses Used?

Transfill hoses are widely used in both recreational support operations and professional technical diving environments.

The most common applications include:

• pressure equalisation between scuba cylinders;
• transferring compressed air from one cylinder to another;
• filling stage and decompression cylinders;
• preparing Nitrox and Trimix breathing mixtures;
• gas blending operations;
• CCR cylinder preparation and maintenance;
• equipment servicing performed by dive centres and qualified technicians.

Although these systems are widely used within technical diving, they are never intended for use during a dive. They are designed solely for controlled gas transfer carried out on the surface.

Types of Scuba Transfill Hoses

Several types of transfill systems are available depending on the intended application and cylinder configuration.

• Complete transfill hose assemblies, supplied ready for use with valves and fittings.
• Replacement transfill hoses, ideal for servicing or custom-built systems.
• Complete gas transfer kits, including hoses, valves and pressure gauges.
• Fittings, adapters and spare parts, allowing maintenance or custom configurations.

Selecting the appropriate solution depends on the gas being transferred, the cylinder connection and the operating pressure of the system.

DIN 200, DIN 300 and INT/Yoke Connections

Scuba transfill hoses are available with different connection types depending on the cylinder valves and the operating pressure of the system.

• DIN 200 bar: the standard connection used on most recreational scuba cylinders rated to 200 bar.
• DIN 300 bar: designed for 300 bar cylinders and commonly used in technical diving. Many 300 bar fittings can also be used with 200 bar valves once the insert has been removed.
• INT / Yoke: the international yoke connection still widely used on many recreational scuba cylinders and filling systems.

Before purchasing a transfill hose, always verify the connection type fitted to both the donor and receiving cylinders. Using incompatible fittings may prevent proper sealing or create unsafe operating conditions.

Compressed Air, Nitrox, Trimix and Oxygen Applications

Scuba transfill hoses can be used with different breathing gases depending on the application and the specifications of the individual components.

• Compressed Air: the most common application for transferring gas or equalising pressure between scuba cylinders.
• Nitrox: widely used in recreational and technical diving. Components must be compatible with the intended oxygen concentration.
• Trimix: used during technical diving and gas blending operations requiring precise gas transfer.
• Oxygen: whenever hoses are used with high oxygen concentrations, every component must be specifically prepared for oxygen service (O₂ Clean) and maintained according to the manufacturer's recommendations.

Using equipment that is not approved for oxygen service may create serious safety hazards. Always follow recognised oxygen-clean procedures and the recommendations provided by the equipment manufacturer.

Transfill Hoses for Technical Diving and CCR

Transfill hoses are widely used in technical diving and closed-circuit rebreather (CCR) operations, where accurate gas management is essential.

They are commonly used during the preparation of diluent, oxygen and bailout cylinders, as well as for gas blending and cylinder pressure equalisation.

Unlike standard regulator hoses, transfill hoses are designed exclusively for controlled surface operations and are never intended for underwater use.

Gas transfer procedures should only be carried out by trained personnel using suitable equipment and following recognised safety standards.

Transfill Fittings, Adapters and Spare Parts

In addition to complete hose assemblies, professional gas transfer systems often require dedicated fittings, adapters and replacement components.

Our range includes DIN fittings, adapters, replacement O-rings and other spare parts designed to maintain reliable sealing and long-term performance.

Regular inspection of sealing surfaces together with periodic replacement of worn O-rings helps minimise the risk of leaks during high-pressure gas transfer operations.

You can also browse our dedicated category of Transfill Fittings & Adapters for compatible replacement components.

Related Categories

Complete your professional gas transfer system with products from our related categories:

• Scuba Regulator Hoses
• BCD & Drysuit Inflator Hoses
• HP Pressure Gauge Hoses
• Scuba Hose Accessories
• Scuba Pressure Gauges
• Scuba Cylinders
• Inflation Systems

Quality, Safety and Maintenance

Scuba transfill hoses operate under very high pressure and are used during critical gas transfer operations. For this reason, only high-quality components that are compatible with the intended breathing gas and maintained in excellent condition should be used.

Before each use, inspect the hose assembly for cuts, cracks, damaged fittings, worn sealing surfaces or any signs of leakage. Any damaged component should be replaced immediately before operating the system.

When working with oxygen or high oxygen-content breathing mixtures, every component must be specifically prepared for oxygen service (O₂ Clean) and handled according to recognised oxygen-clean procedures.

Gas transfer operations should only be performed by trained personnel using appropriate equipment and always within the working pressure limits specified by the manufacturer.

Useful Resources

• Scuba Cylinders
• Scuba Regulator Hoses
• BCD & Drysuit Inflator Hoses
• HP Pressure Gauge Hoses
• Scuba Hose Accessories
• Inflation Systems

Buy Scuba Transfill Hoses Online at Momodive

At Momodive you'll find a complete selection of scuba transfill hoses, complete gas transfer kits, fittings, adapters and replacement parts for professional and technical diving applications.

Our range includes solutions compatible with DIN 200, DIN 300 and INT/Yoke connections, suitable for compressed air, Nitrox, Trimix and oxygen service where specified by the manufacturer.

If you need help selecting the correct transfill hose, fitting or gas transfer system, our team will be happy to assist you in choosing the most suitable solution for your equipment.

Frequently Asked Questions about Scuba Transfill Hoses

What is a scuba transfill hose used for?

A scuba transfill hose is designed to transfer breathing gas safely between scuba cylinders during pressure equalisation, cylinder filling and gas blending operations. It is intended exclusively for surface use.

Can I use a transfill hose with Nitrox or oxygen?

Yes, provided that every component is compatible with the intended breathing gas. When used with high oxygen concentrations, all components must be suitable for oxygen service (O₂ Clean).

What is the difference between DIN 200 and DIN 300?

DIN 200 and DIN 300 fittings mainly differ in thread length and pressure rating. Always ensure that the hose fittings match the cylinder valves being used.

Are scuba transfill hoses used underwater?

No. Transfill hoses are designed exclusively for controlled surface gas transfer operations and must never be used during a dive.

When should a transfill hose be replaced?

A transfill hose should be replaced immediately if it shows cuts, cracks, bulges, damaged fittings, worn sealing surfaces or any sign of leakage. Regular inspection before every use is strongly recommended.