Duotight - 8mm (5/16”) Female x 8mm (5/16”) Female One Way Check Valve (Gas)

Duotight - 8mm (5/16”) One Way Check Valve (Gas)

The duotight 8mm (5/16”) Female × 8mm (5/16”) Female One‑Way Check Valve is a simple but essential upgrade for any gas system. Designed to protect your regulator and prevent backflow, this check valve opens at just 1 psi, making it ideal for CO₂ distribution, gas‑line safety, and clean‑water applications.

Built with stainless steel internal components and EPDM seals, it delivers long‑term reliability even under frequent pressure cycling. Whether you’re running multiple kegs, splitting gas lines, or building a custom manifold setup, this check valve ensures gas flows in one direction only — keeping your system safe, stable, and contamination‑free.
Why duotight? Superior Sealing, Zero Hassle

duotight fittings use a double O‑ring sealing system, giving you twice the sealing surface of standard push‑fit fittings. This dramatically reduces the chance of leaks and allows the hose to bend at tighter radii without compromising the seal.

EPDM O‑ring: excellent gas and chemical resistance
Silicone O‑ring: maintains shape and sealing performance in sub‑zero conditions
Combined: the most reliable push‑fit seal on the market

No clamps are required — just cut your EVABarrier line straight, push it in, and enjoy a secure, gas‑tight connection. To remove, simply push the collet in and pull the line out.

(Suitable for gas or clean liquids such as water. Rated up to 100 psi.)

Key Features

• One‑way check valve for 8mm (5/16”) duotight systems
• Protects regulators by preventing backflow
• Low opening pressure: 1 psi
• Stainless steel internal components
• EPDM seals for long‑term reliability
• Works with gas or clean liquids
• Double O‑ring sealing for leak‑free performance
• No clamps required — simple push‑fit installation
• Rated up to 100 psi