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Fit tool · 60 seconds

Find out if it fits
before you order it.

Almost every return in this category is a thread mismatch, not a quality problem. Three connections look nearly identical to the eye and differ by about a millimetre. Pick the measurement you can actually take, and this page will tell you what you have.

Step 1

Take one measurement

Any one of these three is enough. Use whichever is easiest to get to.

About this head: it ships fitted with a 7/8”-20 UNEF male thread on the spray handle, which is the standard hose-end connection on US commercial pre-rinse units. With the handle removed, the valve body itself is 3/4”-14 UNS. Our Brass Chrome model goes one step further and offers an optional 3/4”-14 end thread for installs that run without the handle — see that model →
Reference

How to take each measurement

1

Count the peaks

Lay a ruler along the thread and count the raised crests across a quarter of an inch. Five means 20 threads per inch. Three or four means 14 — a pipe thread.

2

Measure across

A caliper across the widest point of the male thread. A ruler is not accurate enough here: the difference between a match and a mismatch is about one millimetre.

3

Look at the shape

Hold it sideways. If the fitting gets visibly narrower toward the tip it is tapered — an NPT pipe thread. Parallel means it could still be any of the other three.

ThreadOutside diameterPeaks per ¼”Tapered?Fits?
7/8”-20 UNEF about 22.2 mm 5 No — parallel Yes
3/4”-14 UNS about 19.1 mm 3–4 No — parallel With the handle removed — or the Brass Chrome model's 3/4”-14 option
1/2” NPT about 21.2 mm 3–4 Yes No
G 1/2” BSPP about 21.0 mm 3–4 No — parallel No

The full walkthrough, including what to do when the old head will not come off, is in the thread and fit guide.

Close-up of the 7/8-20 UNEF male thread on the Achelous pre-rinse spray handle
The 7/8”-20 UNEF male thread you are matching against — parallel, 20 threads per inch.
If it does not fit

Send us a photo instead

If the verdict says no, that is a real answer and not a sales pitch. There is no commercially available adapter between a 7/8”-20 UNEF commercial thread and a household 1/2” NPT fitting — people have looked. Buying this head hoping to make it work on a home faucet wastes your money and our time.

If you are still not sure, describe the faucet and your measurement on the fit question form. Someone reads every one.

Check current price and specs on Amazon
Confirm before you buy. Flow rate and temperature rating are not stated on the product packaging — check those on the listing. The thread is the part that most often goes wrong, and it is the part this page settles. The box does include a lifetime warranty card and a bag of spare filters and O-rings.