I purchased an Apple thunderbolt to firewire adapter but the thunderbolt plug will not fit into my Mac 12.5" computer

Thank you, Malcom. I have now ordered the correct adapter. The copy on the Amazon site did not specify that the one I purchased was for older computers. I have already been able to get the right connections and my printer is functioning.

I really appreciate your help.

I need another adapter to connect the one I purchased to the Thunderbolt 3 on the back of my computer. I am trying to connect my old Epson printer to my new computer and this didn't do it.