* Delete 4 Part 6628 Black Technic, Pin with Friction Ridges Lengthwise and Tow Ball (Undetermined Hole Type)
* Add 4 Part 6628a Black Technic, Pin with Friction Ridges Lengthwise and Tow Ball with Round Pin Hole
Comments from Submitter:
Parting out 20 sets all had only "a" variant.