No, the Sony Alpha A9 III is not compatible with the Sony Tough G 128GB CFexpress Type B.
Sony A9 III accepts only CFexpress Type A and SD cards. The Sony Tough G is CFexpress Type B — a physically different and larger form factor that cannot fit either of the A9 III's combo slots.
What works instead
See all compatible camera for the Sony Alpha A9 III →“CFexpress Type B memory cards cannot be used.”
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