CSI Part Number
This Piston is used in the Tailstock assembly of 192 winders, among others. This particular piston is ported to be able to install an air-check valve used on some 192D winders.
See 192D & 192S Winder Parts Book - Plate 5 "Tailstock Assemblies."
4 per Winder
Cylinder Tailstock (CSI-C10007674)