Heat, serve, freeze, and transport in these toxin-free, reusable containers that combine the best of glass and plastic storage containers. Shatter- and heat-resistant borosilicate glass is encased in a protective, multifunctional silicone sleeve. It forms an air cushion that helps protect the glass if you drop it. The dual seal lid forms an almost airtight lock over the glass and the sleeve. To help identify what’s inside, write on the silicone with a dry erase marker, then simply wash it off.