Schmidt K1 Economy Push In Fountain Pen Ink Converter, Standard International Standard Size, (Pack of 3)

The product arrived timely and in good condition. It fits snuggly and functions as expected. I will reorder.

This worked for it's intended purpose, and fits the Amazon Basics Fountain Pens. However, these are rather flimsy in terms of construction, so I can definitely see why you'd want three of them at a time. You get what you pay for, I suppose but these could have been a little better in terms of the construction.

Long term durability is probably limited by the piston gasket (which looks identical to the K5), though it's possible that the converter mouth on this variant might be more likely to stretch or crack than the metal reinforced K5.As far as piston movement, seal to the pen and ink capacity, there's no real difference, except price.Noticeably better feel than "off brand" versions.

Worked and fit my Ohto Celsus pen perfectly. The more expensive K5 didn't.

That is not a Schmidt converter

I bought the Muji aluminum fountain pen that does not come with a converter and this one fits like a glove.

There is no problem with my pen.

The piston is wonderful, but it is too long for most of my fountain pens. Next time I'll measure before I order.