GlassTainers™:These highly durable, shock resistant, and fully tempered glass containers are two to three times stronger than normal glass of similar thickness. “GlassTainers” will withstand temperatures of 275 degrees Fahrenheit and are freezer, microwave, dishwasher safe, with the ability to be microwaved directly from the freezer. “GlassTainers” are popular with every demographic and are our best seller. “GlassTainers” have four integrally hinged snap/lock flaps on a clear plastic lid which, when engaged in closed position, forms an air and liquid-tight seal.