I've bought two Vanishing Point pens, one in 1999 and the 2014 LE. Both came with these caps. This metal cap sets the precise length of the nib assembly so the mechanism properly retracts and the seal valve closes. When using plastic cartridges (either new or refilled) the mechanism presses against the soft plastic. This well made, mirror finished stainless steel cap prevents that. BUT, THESE DO NOT COME WITH THE NIB ASSEMBLIES! I forgot that when I ordered the new 1.0 stub nib for the VP and will be ordering one of these for it with my next order. Using the Con-20 converter, but prefer cartridges so I can check the ink level in them. I want the larger capacity than you get with the Con-50 converter.