No, the ProGrade Digital CFexpress Type B Gold 128GB is not compatible with the Sony Alpha A9 III.
Sony A9 III accepts only CFexpress Type A and SD cards. ProGrade Gold Type B is CFexpress Type B — a physically different form factor that does not fit the A9 III's combo slots.
What works instead
See all compatible memory card for the ProGrade Digital CFexpress Type B Gold 128GB →“CFexpress Type B memory cards cannot be used.”
Last verified:
Confidence: inferred