Cleartone Phosphor Bronze strings 12-53, gauges 12-16-25-33-43-53. Your acoustic guitar will never be quite the same. Cleartone acoustic strings start off with premium phosphor bronze construction. The award winning and patented Cleartone Treatment is next. At only one micron thin, there is no flaking, no slippery feel or dampened tone. All strings in a set feature the Cleartone Treatment for long life and pure tone without compromises.