Technical Specifications & Fitment Guide:
In the plumbing industry, names can be confusing. Our 3/8" Compression Valve Caps are specifically crafted for the standard angle stop valves found in most North American homes. To avoid the common mistake of buying the wrong size, please follow this measurement guide:
How to verify your fit:
Use a caliper or ruler to measure the Outer Diameter (OD) of your valve's male threads. If your measurement is approximately 9/16 inches (which is 1.43 cm or 14.3 mm), then our 3/8" Compression Cap is the perfect fit. Please note that this product will NOT fit 1/4" threads (1.11 cm), 1/2" FIP threads (2.13 cm), or standard 7/8" toilet fill valves.
Why does my 3/8" Valve measure 9/16"? (Understanding Plumbing Sizes)
We know plumbing measurements can be frustrating. The most common mistake is thinking 3/8" means the thread is 3/8" wide on a ruler.
The Industry Name: 3/8" Compression is the name of the fitting.
The Physical Reality: The actual male thread on your wall valve (angle stop) measures 9/16 inches (which is exactly 1.43 cm or 14.3 mm).
The Solution: If your ruler shows ~1.43 cm, our 3/8" Compression Cap is the perfect, intended match.
How to Install in 3 Easy Steps:
Step 1: Confirm your male valve thread OD is 1.43 cm (9/16").
Step 2: Place the included rubber gasket inside the brass compression valve cap.
Step 3: Hand-tighten the 3/8 in stop valve fitting cap onto the valve, then use a wrench for an extra 1/4 turn to lock the seal.
Fitment Checklist:
Fits: Standard North American Angle Stop Valves (3/8" Compression).
Does NOT Fit: 1/2" FIP (2.1 cm), 1/4" Compression (1.1 cm), or 7/8" Toilet Fill Valves.
Commonly Used For (Typical Applications):
This 3/8" cap is the standard size for sealing off water lines on the following household fixtures:
Kitchen & Bathroom Sinks: Shut-off valves (angle stops) located under the cabinet.
Dishwashers: Capping the dedicated supply line when the appliance is removed.
Toilets: The water inlet valve on the wall leading to the toilet tank.
Ice Makers & Refrigerators: 3/8" water supply lines for fridge water dispensers.
Bidets: Sealing off the 3/8" side port on a T-adapter valve.