A sealing ring fits around the inside rim of the cover and forms a pressure-tight seal between the cover and the body of your Tower pressure cooker during cooking. You can fit them yourself or ask your local supplier to do the fitting for you. Check that the sealing ring you order is right for your pressure cooker. Only use Tower sealing rings for your Tower pressure cooker. Compatible with Tower 4L Pressure Cooker Aluminium (7115008).