Martin M400 Bronze Light Mandolin Strings are made from 80/20 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. Martin strings are high-quality strings designed for daily use. Core and wrap wires must meet strict requirements to make the grade. Martin mandolin strings are wound to precise specifications. Gauges 10-14-24-34.