I purchased the piston converter to replace the squeeze converter that came with my Pilot Metropolitan. It is a perfect fit for the pen and I have had no issues using or filling the converter.
I love the Pilot Metropolitan series (I own 14 of them, which I keep filled with inks of different colors). I decided to replace all the original, squeeze converters with CON-40 converters to eliminate three nuisances. First, the CON-40 is transparent, so one can see the amount of ink left and thus whether the pen needs to be refilled. Second, when one stores a pen properly with the nib up, a bubble will usually rise to the nib-end of the converter. When the pen is subsequently inverted to write, sometimes the bubble will rise to the opposite end, but sometimes not, in which case it is necessary to tap on the body of the pen to free the trapped bubble so that the ink can flow down to the feed. The agitators in the CON-40 instantly bring the ink down with them into the proper position. Third--and again a problem resulting from a stubborn bubble in the squeeze converter--if one has been writing with the pen and has stored it with the nib up (and the cap on), a bubble in the squeeze converter will sometimes remain at the end of the converter away from the nib (i.e., under the ink). If there is then a drop in ambient barometric pressure or a rise in ambient temperature, the trapped bubble can expand and force ink up into the feed and the cap and onto the gripping section, so that one gets inked fingers the next time one starts to write with the pen. Again, the agitators in the CON-40 prevent this problem. All in all, this user finds the additional expense for the CON-40 well worth it.
It is my very first fountain pen and I already love it! It has a very good amount of weight. Got it in a fine tip and also got a con-40 to be able to use liquid ink. The construction seems great, I don’t get the feeling like it will break.
Truly great and can’t wait to get myself some other pens :D
I bought this to use instead of the converter that came with my Pilot Metropolitan. It seems to load the same amount of ink--the real benefit of switching is transparency. I can now see the level of ink left in the converter. The converter construction seems to be a bit flimsy (not what I'd expect from Pilot) but it works and I'm happy with the purchase.