Prepare your portion control diet in advance! Top choice by fitness experts these handy 1 compartment bento boxes with clear lids are designed for easy meal prep. Made of safe POLYPROPYLENE they are engineered for heat and cold resistance. It's thick walls keep cold items cold and hot items hot. These versatile lunch containers are microwavable for the ideal take out container. They are easy to stack in coolers and picnic baskets ; Improved AIRTIGHT lid keeps delicate foods fresh!