I love this pen! I used to steal my dad's when I was a child. I still have his stolen pen here!
Now I've tried to restore it - it hasn't flowed any ink consistently, I've resorted to another restoration technique, and I've ordered a replacement nib and clip from
www.penhome.co.uk - so I should get this great cheap pen up and writing in no time! These guys occasionally stock the pen s/h. They just sold a loverly green one I missed! But they always have nibs and clips in stock in various thicknesses too.
From what I know, the 25 was a cheap student pen, which was unusual because of it's stainless steel construction, which gives it a great longevity in terms of condition. The nib was quite springy from what I remember, and you could almost get a calligraphic result from it.
It came with a vacumatic sac (and mine still works), and one of the things I like on it is the design. The Tombow Object is similar in that the top of the main barrel tapers to allow posting to be unobtrusive, a feature I like a lot. The other Parker I own (Frontier) doesn't post well at all, and I tend not to have it so.
It may not be a classic in terms of Pelikan, Shaeffer, et al, but it is somewhat of a 'cult classic'.
I hope this helps. I'll remember to write a bit and post some writing samples of this fine pen.