The Kaweco branded international converter has been very reliable for me, for both the Dia2 & my present Kaweco Specials.
I have seen this converter in three different configurations with "Kaweco" printed on each of their piston tubes. All of them can be fully disassembled for thorough cleaning. I have no idea who makes these converters for Kaweco, perhaps Schmidt.
In the beginning I had problems with poor suction, with bubbles in the tube, instead of filling the chamber with ink. I first blamed the converter, but it turned out that the connection between it & the feed's nipple was the real problem.
You have to push down firmly to attach the Kaweco converters onto the Bock 060 feeds. When filling, you will first get some bubbles in the converter, but if you cycle your converter at least three times, you should get an almost full tube of ink.
At least, this has been my experience.
Edited by tinta, 14 May 2020 - 21:55.
*Sailor 1911S, Black/gold, 14c. 0.8 mm. stub(JM) *1911S blue "Colours", 14c. H-B "M" BLS (PB)
*2 Sailor 1911-M Burgundy/gold pens: 14c. 0.6 mm. "round-nosed" CI (MM) & 1.1 mm. CI (JM)
*Sailor Pro-Gear Slim Spec. Ed. "Fire",14c. (factory) "H-B"
*2 Kaweco SPECIAL fountain pens: 14c."M" "B",-0.5 mm & 0.7 mm stubs (PB)
*Kaweco Stainless Steel Lilliput, 14c "B" -0.6 mm. stub (PB)
*Montblanc 254, 14c. "BB" (1.1 mm?) flügelfeder factory stub