  Blazars constitute the most interesting and enigmatic class of extragalactic
gamma-ray sources dominated by non-thermal emission. In this Letter, we show
how the WISE infrared data make possible to identify a distinct region of the
[3.4]-[4.6]-[12] micron color-color diagram where the sources dominated by the
the thermal radiation are separated from those dominated by non-thermal
emission, in particular the blazar population. This infrared non-thermal region
delineated as the WISE Blazar Strip (WBS), it is a powerful new diagnostic tool
when the full WISE survey data is released. The WBS can be used to extract new
blazar candidates, to identify those of uncertain type and also to search for
the counterparts of unidentified gamma-ray sources. We show one example of the
value of the use of the WBS identifying the TeV source VER J 0648+152, recently
discovered by VERITAS.
