Question about Pogo fork parts

Hi all. I've rebuilt forks in the past but never really questions what each of the parts actually does because I just go ahead and replace these parts. Maybe someone here can shed some light on this for me.

https://sep.yimg.com/ca/I/dratv_2269_13740124 is a picture of the exploded view.

The question I have is on part number 6 and 11. 6 is the slider of course and is responsible for the forks "slop" right? What is the purpose of 11? Is that also supposed to deal with "slop"? On this particular set of forks I just took apart, 11 is split and looks quite worn. I was wondering if it matters to put it back in or if I could make one of PVC or aluminum or something?

Those upper piston slides are über important. When they fail, or wear out, you'll get miles of slop & truly evil handling.

The plastics used were selected for their toughness self-lubricating properties and embedibility. Any grit or dirt will abrade the softer plastic, which is easily replaced, instead of the metal parts.

Not the best setup but very rebuildable. Aluminum piston slides would rattle.

What of part 11? what is the purpose of 11 then? It also appears to be harder to find part 11.

#11is a single part...while still intact.

https://sep.yimg.com/ay/dratv/piston-ct70k0-hk0-z50r-all-fork-slider-1-16m-51c-3.gif

ah ha! Now it makes sense.