Screw-adjustable 510 connectors from Zen/American Modders Supply Co. Supreme quality as Zen is known for. From the Manufacturer:
Are you tired of using Chinese made 510 connectors on your high end mods?
Want something made in the good ‘ol USA with an actual warranty, replaceable solid alloy 101 copper adjustable center pins and available in 316L Stainless Steel OR Solid Copper? Well here you go… the new American Modders Supply Co. 510 connector.
Adjusting pin is reverse-threaded. Positive lead can be soldered directly to the pin guide assembly or to supplied ring terminal.