3/8" BSP female threads on to the portafilter body. Fits most models/makes. These can be challenging for some to install. Many times the thickness of chrome on either this spout or the threads on the portafilter (or both), varies, and getting the spout to thread on may require more than one attempt. It may also require a bench vice to tighten it enough to achieve the desired orientation.
WARNING: This product can expose you to chemicals including lead, which are known to the State of California to cause cancer, birth defects, or other reproductive harm. For more information, go to www.p65warnings.ca.gov.