Review on Gel Pen Refills Set - 48 Vibrant Colors, Including Green and Earth Tones. Ideal for Adult Coloring Books, Craft Markers, Scrapbooking, Painting, Writing, Art, and Drawing. No Duplicate Shades. by Kim Sanchez

I bought these refills during the Revain Prime Sale for about $5. I figured even if half of them were defective it would still be a good $5 deal. Well, inside each of them there are several air bubbles as shown in the picture. There are also dark colored air bubbles, but they are not that noticeable in the photo. As such, none of these refills can be used and they all end up straight in the bin. It seems that each of these gas stations is defective, which has not passed quality control. Well, maybe that's why they're cheap. Lesson learned again: you get what you pay for. Next time I'll just buy refills from OfficeGoods as before. They are more expensive, but their quality and customer service are excellent.