Natural shell buttons, approximately 11.5mm across and 1.5mm thick. They have flat backs. These are polished and have a pearly sheen to them, but they're not quite as shiny as they look in the photos.
I take care to pick the best available buttons for each order but, since shell is a natural material, there may be slight imperfections and variations in colour. Please wash with care - avoid using acidic cleaners and tumble-drying.