How do I tell if my bottle neck is 28/400?

Measure straight across the threads at the mouth of the bottle. 28/400 means 28 mm across (about 1.1 inches) with the standard 400-series one-turn thread. If it measures 28 mm, any 28/400 pump will screw on and seal; 24 mm means the smaller 24/410 family.

How to tell if your bottle neck is 28/400

Measure straight across the threads at the mouth of the bottle: 28/400 means 28 mm across, with the standard 400-series thread profile. A kitchen ruler or tape measure is accurate enough; you are checking for 28 mm, roughly 1.1 inches.

The first number in a neck size is always the thread diameter in millimetres. The second describes the thread style; 400 is the everyday one-turn thread found on most soap, lotion, and Boston round bottles. If your bottle measures 28 mm across the threads, any 28/400 pump will screw on and seal.

Common signs you have a 28/400 bottle: it is a standard soap or lotion bottle, the cap or pump turns off in about one full rotation, and the opening is a little over an inch wide.

If it measures 24 mm you have the smaller 24/410 family, and our pumps will not fit. We would rather tell you that here than after you order.

Replacement Soap Pump · 28/400 — 304 stainless steel, ten finishes, $7.49