Bock Stainless Steel nib unit with feeder and threaded housing.
Size 6, that means that the feeder is 6 millimeters in diameter. Thread housing M7.9x0.6.
Modified by FPnibs to add flexibilty: up to 1 millimeter tines opening.
It is medium soft, that means you need to apply a bit of pressure to open the tines.
Modified feeder to increase ink flow.
Works well with cartridges and converters, but bigger ink reservoir would be even better.
You must learn the limits of this nibs in order to avoid a permanent tines spread due to too much pressure. In this case we would not replace or repair the nib for free.
All our nibs are adjusted and tested to perform at their best if used properly.
Extra care must be taken when screwing and unscrewing the nib unit into your pen, because it may misalign the tines.