netfabb Basic is a freeware for stl-format files handling. This app is not just a viewer, it provides mesh edit, repair and analysis capabilities to everyone already being or aspiring to become part of this fantastic, growing, creative, high-tech industry called Additive Manufacturing, Rapid Prototyping or 3D Printing.
What kind of "freeware" requires a dongle and/or a product key before it can be downloaded? That's not freeware!