Canon YG2-2062 Power Diaphragm
Genuine Canon power diaphragm assembly for the EF 24-70 2.8 L USM lenses. Made by Canon Japan. Unfortunately, this part has been discontinued and is no longer available.
TechNote. Many times the issue you may have with your lens points to the power diaphragm unit, when actually the FPC (flexible printed circuit) has broken and needs replacement. In stock here.
Canon YA2-0124 Friction Rubber
Canon YB2-1326 Collar Screw
Genuine Canon screw to retain all sizes of collar YB2-1328 for the EF 16-35 2.8 L II USM lenses and other Canon imaging products.  Package of 1 screw. Made by Canon Japan.