No Back-Up Washer!?

[Vietnow]

After waiting all day to get home from school and install my new lvl 10 its missing the first part I need. I opened the little baggie of parts onto a white sheet of paper so I am sure I did not lose the Back-Up Washer. Can I skip this part or am I going to have to call AGD and wait another week? Thanks for your time.

[Dayspring]

You NEED that white delrin washer. It's what keeps the oring in the powertube and not in the valve assembly.