Guitar Strap Jack Endpin Adaptor by Pinegrove Leather
1pc. Chrome Screw-Mount Stereo Endpin/Strap Button Jack - C. B. Gitty Crafter Supply
Guitar Pickup Endpin Jack Plug Sockets for Guitar 3 Prong Chrome Threaded Cycinder Long Guitar Bass Output Jack Hot|Guitar Parts & Accessories| - AliExpress
End Pin - Ebony Guitar - Greg Boyd's House of Fine Instruments