Best strings I have tried. They last an EXTREMELY long time. Very flexible, but maintain tension (.124 Kalium has more tension than .135 D'Addario). Great growl. Plenty of zing when new(if you like that), but mellow out after a while and maintain this tone for a LONG time. I have been rotating the same few sets for two years with just taking them off and soaking them in denatured alcohol overnight. I play a set about a month and then rotate. After a soak, they sound like they are only a couple of days old again. This is after more than a year! The smaller strings are starting to show fret wear, but if you played fretless they would last until you broke one!
Kalium/circle K Hybrid Balanced .124 Six String Set
Balanced Tension Hybrid nickel/steel round wound strings