Product Name: BT Thermo Neck Warmer Product Number: JW-120 Specifications Color: Black Size: Free Size Quality: Polyester, Acrylic, Others Long-lasting warmth with Tech Thermo. What is Tech Thermo? It is equipped with Tech Thermo, which uses special rayon with the latest technology that not only provides insulation but also has a heat-generating effect. It reacts to moisture such as steam constantly emitted from the human body, and the fibers quickly generate heat and also sustain it. Features ・Heat-generating thermo. ・Insulation effect.