Ernie Ball's RPS wound strings consists of specific gauges and core to wrap ratios for balanced rich harmonics and that signature Slinky feel. Plain strings in RPS sets last longer and stay in tune better than conventional plain strings. A patented winding of brass wire is tightly wrapped around the lock twist of the ball end of the plain strings. String slippage and breakage are minimized at the ball end where these most often occur. Gauges .009, .011, .016, .026, .036, .046