| 主权项 |
1. An adapter comprising:
a neck with threads arranged to receive a ring that holds a nipple snug on the neck; and, a plurality of rings of threads located within an interior of the adapter, each ring of threads having a different diameter, the interior being tiered so that a first ring of threads closest to an opening at a bottom of the adapter has a widest ring diameter and a second ring of threads farthest from the opening at the bottom of the adapter has a narrowest ring diameter. |
