Gauges 11.5-14-23-28-38-47. Martin M1400 Marquis Acoustic Folk Guitar Strings are specifically designed to give you excellent tone, clarity, and response. The Marquis silk-wrapped ball end helps reduce wear on the bridge and bridge plate, making them ideal for valuable, vintage instruments. Martin Strings are high-quality strings for daily use. Core and wrap wires must meet strict requirements to make the grade. Martin Strings are wound to precise specifications.