The B1031BK is a 16 oz black HDPE plastic boston round bottle with 28-410 neck finish. The boston round bottle is distinctive in its classic shape. Characteristic of the boston round are its rounded shoulders and rounded base. High density polyethylene (HDPE) is marked with the resin identification code of 2. HDPE has a high tensile strength, good resistance to chemicals, good impact resistance, highly rigid, and highly scratch resistant. This item has a 28-410 neck finish. The first number refers to the diameter (in mm), and the second refers to the closure depth, style and thread. This container can be paired with a closure with a matching finish.