Usually, the material of hard tag is HIPS(High impact polystyrene) and ABS(Acrylonitrile butadiene styrene).

HIPS is a low cost PS material that is easy to machine and fabricate. HIPS is often specified for low strength structural applications when impact resistance, machinability, and low cost are required.It is frequently used machining pre-production prototypes since it has excellent dimensional stability and is easy to fabricate, paint and glue. Natural (translucent white) HIPS is FDA compliant for use in food processing applications. The following physical property information is based on typical values of the base high impact polystyrene resin.

ABS is an amorphous thermoplastic blend. The recipe is 15-35% acrylnitrile, 5-30% butadiene and 40-60% styrene. Depending on the blend different properties can be achieved.
Acrylnitrile contributes with thermal and chemical resistence, and the rubberlike butadiene gives ductility and impact strength. Styrene gives the glossy surface and makes the material easily machinable and less expensive.
Generally, ABS has good impact strength also at low temperatures. It has satisfactory stiffness and dimensional stability, glossy surface and is easy to machine. If UV-stabilizators are added, ABS is suitable for outdoor applications.