Chain link centerstop (Part #CS-CS-A) is shown below upside down.   The hole in the center is for sliding in a piece of pipe.

  cl-cs-a1.jpg (41131 bytes)

Dimensions:
Diameter = 6-5/8"
I.D. (Inside Diameter) of Bottom Peg= 1"
O.D. (Outside Diameter) of Bottom Peg = 1-3/8"
Peg Length = 1-5/8"
Material = Aluminum