Lip design is a kind of special treatment given to the top of plastic products like bowl, bucket and all kind of plastic containers to provide the strength to the product. Lip design may vary with the usage of product. Plastic bucket and small bowls have an L-shape lip over the top. Medicine bottles and other PET bottles have a solid protruding ring at the top. Apart from giving the desired strength to the part lip may have other functions like acting as stopper for a cap, preventing a locking between the components during stacking etc.