Unresolved MatterControl convert mm to inch or inch to mm

I am running Mattercontrol. I downloaded 7 Stl files, the first 3 look and printed good. The third file came up in mattercontrol really small. I talked to the person who created the files and he said I needed to convert from mm to inch or inch to mm. He said the files were created in silc3r. There are other files in the 7 that I downloaded that also show up as small in Mattercontrol. He also said not to mess with the scaling of the files.

My question for the forum is does this make sense and is there a way in mattercontrol to convert from inch to mm or from mm to inch.
If this forum has no answer my next post will be to mattercontrol, this forum usually responses faster than mattercontrol

 

Scale it by 25.4 to go from inches to mm