Got a Stanley TRE 300 electric stapler. I want to staple some carpet
pieces to the wood bunks on my boat trailer. Because of salt water
immersion, stainless steel staples are needed.

I've just been told Stanley has quit making this stapler and staples for it.

Stainless steel staples are not available at our local Home Depot and Lowes.

Where can I find a selection of stainless staples that will fit this gun?
I've tried Google, but couldn't find Stainless ones.