This is plastic swivel ball link with adjustable tension by Dubro. This is used in conjunction with 4-40 threaded rods.
Includes: Two each of linkages, brass swivel balls, 2x6.5mm slotted head tension adjustment screws, 2.6x15.5mm hex drive screws, 6.5x3.5x3mm tapered spacers and 2mm hex nuts
Requires: Assembly onto kit and 4-40 diameter rods
Length: 23.5mm (0.925)
Inside Diameter of brass swivel: 3.3mm (0.132)