These were a good price so I figured I'd give them a try. Ordered 2 packs. Pack1:Out of 4 pens in the pack, the black didn't work at all, the blue worked for a bit (Ie, able to write a few words with) before trailing off and ceasing to work. The green and red are okay, too bad really as I mainly ordered these for blue & black ink and as an alternative to using a ballpoint pen.
2nd Pack was the same: 50% work or sort-of work, 50% don't. Disappointing, but not entirely unexpected given these cost about 1/4 as much as other brands for the same thing.