Glasslock is a heat-resistant tempered glass container brand with four-sided locks on lid, which was developed by Samkwang Glass after 4-year-long research. THe products are made of 100% natural glass, preventing colors and smells from being absorbed into containers. They can be put in both microwaves and freezers, and are free of EDC. Since the brand was launched in November 2005, it has gained large popularity in Korea and overseas.