They came on a used Azola Vintage Baby Bass (so probably not stock), and I have no idea what they are. They have a lot of sustain and mwah (they're almost twangy, to be honest), the silk is black on each end of all four strings, and the barrel at the end has no hole- it's solid. They are more flexible than Helicore Orch Meds, if my finger memory is accurate. That's all the info I can provide. Thanks for any help!