The cap for use with this stud is the WCN AR CAP annular ring cap.
Annular Ring (Navy)
3/16"
1/4", 5/16", 3/8", 1/2", 3/4", 5/8", 1-1/4", 1", 7/8", 1-1/2", 1-5/8", 1-3/4", 2", Larger sizes available upon request
Aluminum, Stainless Steel
Imperial
CD (Capacitor Discharge)