Interactive tool
Cartridge identifier tool.
Five traits describe any faucet or shower cartridge. Learn what each one means as you go, then keep the spec sheet. Works on any brand, any era, marked or unmarked.
What kind of part are you holding?
Four different mechanisms sit behind faucet handles, and people call all of them cartridges. They are different parts with different replacement logic, so this is the first thing to settle.
If small springs and cone-shaped rubber seats fell out of the valve body when you pulled the part, you have a ball assembly rather than a cartridge.
Pick one
What does it control?
Count the port openings around the circumference and note whether they sit at one height or two. Two rows of ports almost always means the cartridge mixes hot and cold rather than controlling a single supply.
Shake a suspected pressure-balance cartridge gently. A loose internal spool is often audible, and that sound is diagnostic.
Pick one
How long is it, end to end?
Measure the whole assembly end to end, from the tip of the stem down to the bottom seating face. Include the stem and the retainer. Overall length is one of the most useful numbers you can report and the one most often measured wrong.
Two cartridges can share every other trait on this page and differ only in length, so be precise. If you are using a tape rather than calipers, stand the cartridge on a flat surface and sight straight across rather than at an angle.
Pick one
What does the stem end look like?
The broach is the shaped end of the stem where the handle attaches. Look straight down the axis. It is the trait that most reliably separates cartridges that otherwise look identical, and most people skip it because they do not know the word.
For splined broaches, mark a starting tooth with a pencil, count around once, then count again in the opposite direction to confirm. Worn broaches are easy to miscount by one, and one tooth means a different part.
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How was it held in the valve body?
Something holds the cartridge against line pressure. What that something is tells a specialist a great deal about the family of valve you are working on. Think about what you had to remove before the part would move.
While you are looking, count the O-rings on the body and note roughly where they sit. Three evenly spaced reads differently from two clustered at the bottom.
Pick one
Cartridge spec sheet
Copied. Paste it into your job notes or send it to your supplier.
Nothing is sent anywhere. Answers stay in your browser so you can close the tab and come back to the same job.
Why this works
A part number you cannot read is not a starting point.
Most cartridges that come in for identification carry no legible marking. Either they never had one, or scale and wear took it off. Searching for a number that is not there is the single most common way a cartridge job stalls.
Physical traits do not wear off. Describing them precisely is what makes a fast, certain match possible, and it is a skill that transfers to every cartridge you will ever pull. For the full method behind each question, including the four photo angles that carry the most information, read the cartridge identification guide.
Common questions
About the tool.
Does this tool tell me which cartridge I need?
No, and that is deliberate. The tool builds a precise physical description of the part in your hand: mechanism type, function, length band, broach style, and retention method. Matching that description to a specific orderable part number requires manufacturer cross-reference data and decades of superseded part records. What the tool gives you is the vocabulary and the spec sheet, which is what makes a fast, accurate identification possible in the first place.
Why describe the cartridge instead of looking up a part number?
Most cartridges have no legible part number, either because they never had one or because scale and wear removed it. Physical traits do not wear off. A twenty-tooth broach is still twenty teeth after fifteen years in hard water, and a three-and-a-quarter inch body is still three and a quarter. Describing traits is more reliable than searching for a number that is not there.
What if I do not know the answer to a question?
Skip it. Every question is optional and the spec sheet works with partial answers. Unknowns are themselves diagnostic: telling a specialist the broach is too worn to count is real information, not a gap.
Do I need an account to use the tool?
No. The tool runs entirely in your browser, nothing is submitted anywhere, and your answers are saved locally on your own device so you can come back to a job in progress.
Can I use this for a shower or tub valve?
Yes. The same five traits apply to shower and tub valve cartridges, which tend to be larger and more often pressure-balance or thermostatic. If the cartridge will not come out of the wall, describe what you can see and photograph the valve body and trim.
What do I do with the spec sheet?
Copy it into your job notes, text it to your supply house, print it for the file, or send it to us with photos. It is a plain description of the part, useful anywhere a part needs describing.