Zojirushi Stainless Steel Food Jar has vacuum insulation to provide the best heat retention. Pre-heat or pre-chill the food jar with hot or ice water to keep temperatures longer. Has an easy-to-clean SlickSteel® polished stainless interior. The tight-fitted lied with gasket, seals to minimize leaks and maximize heat retention. The 2.75" wide opening makes for easy filling, eating and cleaning. The lid disassembles for easy and thorough cleaning.