There is a triangular sign, there is a 6 inside, English PS, PS is polystyrene, can not be cup! The temperature is too high will release the cup of chemicals to release hot water, the material must be PP, PP polypropylene is now the safest hot cup, you can put the microwave heating! Grades that are slightly lower may be PC materials. PC cups should not be used less often unless they are labeled as containing no bisphenol A. In particular, infants and young children cannot use it!