Both H&S Ultra and Evolution Silverline models come standard with a single PTFE needle seal packing. These can be upgraded by purchasing additional PTFE needle seal packings and buying the appropriate Needle Seal Packing Screw to accommodate 3 seals. When I contacted MAS to see if these could be purchased, they went out of their way and contacted H & S. They ordered the items and notified me when they arrived. I was also able to purchase the H & S screwdriver that makes doing the upgrade so much easier. Thanks to the team at MAS for taking customer support to a new level.