Hi. I recently bought these secondhand, but the winding has a slight break where it crosses the bridge so they're done for, and there is the metallic buzz when bowed etc! But they sound deep and dark and almost gut like. They are medium to low tension and off the bass do not feel like they have a steel core. They're really flexible. I did a search but that came up as chromecor for the E which has green winding both ends, and sensicore on the A which is blue both ends. But they are the same type of string. The ball end is brass and numbered 3 and 4, for the A and E respectively. I'd like to know what these are because despite the winding issue, the strings sound far better than my helicore heavy orchestrals, and bow much easier.