La Bella RX-N4A bass strings set Nickel Round Wound 40-100. Not all constructions are created equal. Every string in the Rx Series is uniquely constructed for that particular set. This "Focused Set Design" concept helps achieve all the elements of a perfectly balanced set such as tone, feel, vibrato, and tension. More flexible and lighter in tension compared to SN & M Series, players will find the RX Series are more comfortable to play on any style bass. The RX Series is just the remedy your bass has been calling for!