Large 8 x 9mm pivot balls which the ladder bars move on the Tamiya Clod Buster and JConcepts Regulator chassis. Previously, the kit versions were very heavy steel items which required a regular slot type screwdriver for builds. With the JConcepts Titanium pieces, the application is smooth and simple with a 2.5mm wrench while the light-weight material screws together very easily. Fits Tamiya Clod Buster JConcepts Regulator Standardized 2.5mm hex adjustment area 8 x 9 x 4mm ball-stud 4pc per package