The insert holds 6 fl. oz. (3/4 cup) and fits any wide mouth canning jar. This ingenious idea is an eco-friendly alternative to messy disposable hot cups, bulky travel mugs or plastic lunch containers. Canning jars, found just about anywhere, are cheap, heat-resistant, environment friendly, and durable. Designed for beverages, the travel lid has ample room to insert a straw, thus the name Straw-Tek. The BNTO (ben-toh) lunchbox adapter was inspired by the Japanese bento boxes. The insert fits snugly under the metal standard lid of a canning jar to separate into two compartments for yogurt, salsa, dips, salad dressings and more. The design, simplicity and utility of these products shows a commitment to recycling, reducing wasteful disposable cups and plastic containers in landfills. Durable, plastic adapters made from food-grade recycled plastic, and are BPA, BPS and phthalate free. Top rack dishwasher safe. Made in the USA.