The D'Addario are the stock strings that came with my NSD EU5. I think they are supposed to be Helicores. The 5 string set was on my instrument for about 3 weeks, before I switched the higher 4 strings out to the TI Superflexible (orchestra 3/4). Not for me either. They spent even less time on my bass. (I eventually settled on Corelli 370Ms). The 5 string D'addario set is for sale for $60 shipped to the continental US. The 4 string Superflexible set is for sale for $85 shipped to the continental US.