Martin M170 80/20 Bronze Round Wound Extra Light Acoustic Guitar Strings - 4 Pack M170 80/20 Bronze Round Wound Extra Light Acoustic Guitar Strings - 4 Pack The Martin M170 80/20 Bronze Round Wound Extra Light acoustic guitar string 4-pack is a great buy for the player looking to stock up and save time and money The Martin M170 strings employ a composition alloy to give brilliance, clarity and longevity of sound The bronze winding is ideally suited for making strings that have deep, rich basses and clear, bright trebles Gauges 10-14-23-30-39-47