This is a lid for the thermos. A gasket is pre-assembled on this lid so you don't need to purchase one separately. *IMPORTANT* These spare parts will only work with the redesigned OmieBox® model. They will not fit OmieBox® UP. All spare part purchases are non-refundable. If you're not sure which version OmieBox you have, please email us at info@omielife.com. If you're unsure which model you have, please turn your box over. On the back of the box, there is a square box with 8 alpha numeric characters. If the code has the letters SD, it's the original model. If the code has the letters CH, it's the redesigned model.  If you have any questions, please contact us at info@omielife.com.