The 8 oz clear PET cosmo round bottle with 24-410 neck finish. The cosmo round, also called bullet round and imperial round, is characterized by its tall and slender build with steeply rounded shoulders. Polyethylene terephthalate (PET) is marked with the resin identification code of 1. PET is of the polyester family and has high clarity, good chemical resistance, high impact resistance, and medium rigidity. PET is also light-weight and is used for products containing essential oils. Sold in 100 count cases.