This is the official STL model of the new Steam Controller published by Valve (released under CC Attribution-NonCommercial-Sharealike 4.0), made into a 3D print ready profile. You can print it and use it to get a feel whether you like the controller's shape or try to already design accessories for it while waiting for your real one to arrive in the mail.

And just to spell it out clearly, this is just the plastic shell, no internal structures and certainly no electronics are inside it so don't think you will get a functional controller out of this print.