With a good weight of 3.4 pounds ( 54.4 ounces) each,according to th seller, it appears that I have some defective (underfilled/not filled) cartridges.One unused one weighs in at 39.66 ounces, or 2.48 pounds. Another one, which only gave me a few legible pages, weighed in at 32.68 ounces, or barely 2 pounds. The third cart also only gave only a few pages before I took it out of the printer - it weighs 33.59 ounces.I returned these to the seller 2 months ago after they told me they'd give a full refund. I'm still waiting, even after repeated emails to them.