Image Item No. Description By  4274  Technic, Pin 1/2 without Friction Ridges Catalog: Parts: Technic, Pin 1  6558  Technic, Pin 3L with Friction Ridges Catalog: Parts: Technic, Pin 1  6628  Technic, Pin with Friction Ridges and Tow Ball (Undetermined Type) Catalog: Parts: Technic, Pin 1  2780  Technic, Pin with Short Friction Ridges Catalog: Parts: Technic, Pin 1