“Writing after my original review: I purchased a few packs of 10 but then I started noticing that I had a problem and then the number of cartridges I had the problem with multiplied. At first I thought it was a problem with my magnetic ring, thinking that maybe I had worn it out or misused it somehow. By the time the second ring arrived I had realised that the problem was with the notches in the ring and the holes in the bottom of the cartridge not lining up. When I went through my set I found that one ring worked for some and the other worked for others- though only 2 cartridges sat properly with one or the other and two had their holes completely covered by the ring.”
