˙The bottom is made of PP and the upper cover is made of PC
˙The stopcock is made of PC material, and the stopcock valve is made of PE material, which can control the air entering speed
˙With O-RING, strengthen the tightness, no need to apply petroleum jelly
˙Without plastic porcelain plate
˙It can withstand a full vacuum (740mmHg) for 24 hours at room temperature