This is a 48x48 inch playmat designed for 28mm-30mm wargames when printed at full size.
This mat is offered as a 150dpi JPG file, which should be easy for any print shop to accept and work with.
The full playmat measures 49 x 49 inches, which includes a 0.5" bleed on each side.
Here's a look at the full mat:
Here's a closer look at a few select portions of the mat: