Refine STL For Printing

I already have the model as a single STL, but it still needs a little love before it can go to the printer. Please clean up the mesh—remove any non-manifolds, holes, loose shells, and other common issues—then scale the piece to the exact millimeter dimensions I will provide once we start.

Deliverables:
• A watertight, error-free STL ready for slicing
• The same file correctly resized to my millimeter specs
• A quick screenshot or render so I can visually confirm the changes before sign-off

If you work in Meshmixer, Blender, Netfabb, or similar repair tools that’s perfect, as long as the final output is a pristine STL. I’m looking for a fast turnaround and clear communication throughout the process.
I use Einstar Rockit scanner and Bambulab 3d printerr