All of the standoffs featured on our site use a 5/16-18 stud to connect the cap to the barrel.
One stud is included free with each cap, based on material thickness. If you need additional or replacement studs, you may find them here.
1" Diameter Standard Aluminum Gyford Cap
1" Diameter, 1" Tall Complete Aluminum Gyford Standoff Kit
Vinyl Washers for Glass Installation (Gyford Standard Caps)