This model is of the Mirror Shield from The Legend of Zelda Majoras Mask. The Shield isn't Circular. The Printable version is called MirrorShieldMM_No_Handle. The Mirror shield with the handle is just for show.
If you plan to print the Model, print the file called "MirrorShieldMM_No_Handle.stl". This Model may need some (but not much) support material.