Viega 17768 ProPress sealing element FKM, 1/2'' (dull black)

The Viega 17768 is the 1/2 inch ProPress sealing element. One seal goes in each press socket, so a 1/2 inch coupling takes two and a 1/2 inch elbow takes two. Measure across the ring: it runs 0.835 inches across and 0.102 inches thick.

Black identifies the FKM compound. Viega color codes its press sealing elements so an installer can tell at a glance which elastomer is in the fitting, and the 17768 is the dull black FKM version in 1/2 inch.

No. Standard ProPress fittings ship with an EPDM element; the 17768 is the FKM compound, marked dull black. They are not interchangeable choices for the same job, so pick the element that matches the media and temperature the line is carrying, and replace both seals in a fitting with the same compound.

That is exactly what the 17768 is for. It is sold as a loose seal, so if an element is nicked, missing, or you need to convert a 1/2 inch fitting to the FKM compound, you seat the new element in the socket bead rather than scrapping the fitting. The seal must be fully seated and undamaged before the jaw is closed, and a fitting is only pressed once.

Count two per fitting, one per press socket, then add spares. At 0.004 lbs each they cost nothing in weight, and a dropped or rolled seal on a jobsite is the usual reason a crew stops work. Property maintenance and MRO stockrooms running 1/2 inch press lines generally keep a bagged quantity on the shelf for this reason.

Order it as Viega 17768. It is made in Italy. That part number covers only the 1/2 inch size, so larger lines need the matching element for their own diameter rather than this one.

Treat it as a Viega ProPress component only. Press sealing elements are cut to the specific socket bead profile of the system they belong to, and the 17768 is the 1/2 inch ProPress element. Mixing a seal from one press system into another manufacturer's fitting is not something to attempt on a pressurized line.