The body of the Smart Tube appears to be made of plastic. What plastic?

The body of the Smart Tube MTS1P is made of polyethylene.  The cap is made of polypropylene.  Both polyethylene and polypropylene are known as polyolefins.  The specific polyolefins selected for the Smart Tubes were chosen for their exceptional combination of biocompatibility, low temperature performance, and mechanical toughness.