Septa

A system comprising:

• a cap comprising an opening;
• a septum configured to engage with the cap, the septum comprising:
• an annular shaped first portion having a first width, wherein the first portion comprises a rounded-wall portion;
• a second portion having a second width smaller than the first width, the second portion being sized and shaped to be received by the opening of the cap;
• a third portion adjacent the second portion, the third portion having a third width larger than the first width and the second width, wherein the third portion has a constant circumferential width from a top surface to a top surface to a bottom surface of the third portion, wherein the bottom surface has a constant horizontal plane across the circumferential width of the third portion;
• and
• an inert coating disposed on the bottom surface of the third portion defining a terminal end of the septum;
• and
• a vessel configured to engage with the cap, wherein the septum is configured for puncture for fluid movement through the septum and to the vessel, from the vessel, or combination thereof.