Gauges 45-55-80-95. Ernie Ball 2070 Earthwood Acoustic Bass Strings are wound with an alloy of 92% copper, 7.7% tin, and 0.3 % phosphorus. They have a light orange-gold color and provide a mellow, ringing sound with excellent clarity. All Ernie Ball strings are precision manufactured to the highest standards and most exacting specs to assure consistency, optimum performance, and long life.