I used Mistic for about a month (refilled cartridges after the 1st week). I never could find anything, other than Mistic branded products, that would fit it correctly. I've since recently moved on. I actually still keep a Mistic battery and a few filled cartridges around as a backup. One thing I did like about the Mistic, as a starter, is that the battery would last me quite a while and I could carefully refill the cartridges several times before disposing of them.