These ZCI piston heads are most likely made from a nylon composite and come in two different versions. The threads are supported by a brass nut that is cast into the Nylon and these include a lock washer under the screw. This lock washer keeps the screw from working it's way out, a fairly common problem. However, I still recommend you use some thread locker on any piston head. Another nice feature of these is the O-rings seem to be better quality and other ACM brands and they have a fairly good seam. A good seam is very important to a consistent seal in a piston head. The plastic construction combined with the brass nut makes these very strong and very light.
Specifications:
Material: Nylon
Thrust bearing: No
Backer washer material: Polymer
Mass: 7.0 grams
Thickness: 0.303 in (7.7 mm)
This product was added to our catalog on Sunday 28 October, 2012.