KF-25 (NW25) is the most widely used KF size. It's the standard connection on many small and mid-size vacuum pumps, and it's common on lab manifolds, freeze dryers, degassing and distillation setups, leak detectors, and gauge and valve ports. KF fittings are also called QC (quick connect) or QF (quick flange) fittings.
Which KF-25 part do I need?
- Connect two KF-25 parts: Connecting two KF-25 flanges requires one KF-25 clamp and centering ring set.
- Connect to a threaded port: Use a KF-25 to NPT adapter, available in male or female threads from 1/8" to 1".
- Connect to hose: Use a KF-25 hose barb adapter (1/4" to 1") or a PVC smooth hose adapter (3/4" or 1"). Our silicone vacuum tubing fits our hose barbs.
- Add flexibility or absorb vibration: Use a KF-25 stainless bellows, available from 100 mm to 2500 mm.
- Change direction or split a line: Use a KF-25 elbow, tee or cross.
- Change flange size: Use a straight reducer to KF-16 or KF-40, or a reduced tee to KF-16 or KF-40.
- Close off a port: Use a KF-25 end blank.
Frequently asked questions
What are LoCo's KF-25 fittings made of?
All LoCo Science fittings come standard in heavy-duty 304 stainless steel. Our vacuum clamps are offered in both stainless and aluminum to fit your application.
Are LoCo's KF-25 fittings welded or milled?
Our NPT adapters, hose adapters, and flange reducers are turned from solid 304 stainless steel bar, without welds. Our elbows, tees, and crosses are welded parts.
Is KF25 the same as NW25?
Yes. KF25 and NW25 are two names for the same ISO-KF flange size. KF is the most common name; you may also see DN25 or QF25. Parts sold under any of these names connect to each other.
Can I connect KF-25 to other flange sizes?
Yes. We stock KF-25 to KF-16 and KF-25 to KF-40 straight reducers, and reduced tees from KF-25 to KF-16 and KF-40.
