Thermal insulation bachelor cup, product specification: 350ml. Material: vacuum flask, flask 304 inside and 201 outside, inner layer design. Product features: height 22cm, bottom diameter 5.7. Cover design: bounce lock, not easy to open the cover automatically to prevent leakage more thoroughly, it is a good choice for driving crowd. Deep water groove design, effectively prevent water leakage. The cover is made of food grade PP material with two layers of water-proof silicone inside and inside.