No, the Lexar CFexpress Type B Professional Gold 128GB is not compatible with the Sony Alpha A9 III.
Sony A9 III accepts only CFexpress Type A and SD cards. Lexar Professional Gold is CFexpress Type B — physically incompatible with the A9 III's Type A/SD combo slots.
What works instead
See all compatible memory card for the Lexar CFexpress Type B Professional Gold 128GB →“CFexpress Type B memory cards cannot be used.”
Last verified:
Confidence: inferred