Parker VS---is the clear part of the filler unit made of glass or plastic?

That would be the VP, not the VS. The clear part is plastic, and it is VERY FRAGILE! It cracks if you yell at someone else three rooms away. These fillers are almost impossible to find; be prepared to shell out $75.00 or more for one.

Parker VS, 1946:


Parker VP, 1963:

Thank you Richard-- and ooooops---you are correct, I meant the VP. Fortunately it came out with a bit of soaking and a STRAIGHT pull---just as it says on the unit (the straight pull part). Many folks have told me it was glass but a I didn't think so. I've seen some broken ones and the fracture pattern didn't look like glass to me. The nice thing about that one is that it has a 1.5 mm italic nib (apparently original to the pen. T'was used by a fellow who wrote music and the nib made great quarter notes and so forth and a 90 degree turn and one made the vertical line and a partial turn made the "flag". An appropriate music nib substitute?