They put ink only in 1/3rd of the pen and covered the remaining 2/3rd with black paint so it won't be obvious when you buy it. I went through 1 pack ( 5 pens) in 7 days. Stay away from the tricky highlighter
I use highlighters a lot in my work. I like the colors of these but they do not last very long as the highlighter fluid is a bit on the skimpy side and runs out fairly quickly. Not a bad value for the price just wish they offered a "larger" version with more fluid.
Overall I was happy with the product. The colors were very nice and the ink dried quickly. The pens unfortunately bled through the paper and I didn't think the ink lasted that long before it ran out. I use these on my textbooks for college.