I can source various sizes of Round Seal.
If the one you are looking for is not listed then contact me and I will try to help.
Most of these are white of off white, when ordered in I cannot choose a colour.
Freezer Square Rounds Round Spare Lids/Seals and Half Round Quarter Round Seals
Insulated Multi Server
Shape-O Shapo Spare Shapes
Space Saver / Oval Container Spare Lids/Seal