Guest Ball Vlv, 3/8 Tube, Straight

The John Guest Ball Valve, 3/8" Tube, Straight, from Reliance Worldwide Corporation adds an inline shut-off to a 3/8" tube run, letting you control flow with a quick quarter-turn of the handle. With push-fit ports on both ends, it installs in seconds and is ideal for servicing filtration and reverse osmosis systems without draining the whole circuit.

Being able to isolate a section of plumbing without draining the entire system saves time and avoids mess during maintenance. This straight ball valve drops into an existing 3/8" line and provides positive on/off control, so you can change a filter cartridge or service a membrane while keeping the rest of the system intact. Its larger 3/8" bore suits runs that carry more flow than a 1/4" line.

Inline Flow Control

• Connection: Tube x Tube, both ends 3/8"
• Straight inline ball valve with quarter-turn handle
• Corrosion-resistant polypropylene construction
• Push-in collets grip and seal each tube automatically
• Tool-free installation, fully demountable
• Positive on/off control for quick isolation

To install, cut both 3/8" tube ends square and deburr them, then push each fully into a valve port until it seats past the collet. The internal O-rings seal each connection automatically, and a gentle tug confirms the grip on both sides. Operate the valve by turning the handle a quarter-turn, inline for open and crosswise for closed. When the maintenance task is done, reopen the valve and flow resumes normally. Because polypropylene resists corrosion and the chemicals in treated water, the valve performs reliably over years of service without scaling or rusting, and the push-fit connections can be remade as the system changes. Matched to standard 3/8" tubing and built for reliable, repeatable operation, this John Guest straight ball valve is an essential control fitting for residential water treatment plumbing.

Within the John Guest range, this straight valve integrates with the larger 3/8" unions, tees, and elbows that share the same collet system, so isolation can be added anywhere in a higher-flow layout without rerouting. Fitting a shut-off ahead of each serviceable component is a smart habit that turns filter and membrane changes into quick, contained jobs rather than full-system shutdowns prone to spills.