The D’Addario Multi-Tool provides the tools needed for most standard adjustments on your guitar and bass. The multi-tool features US and metric-sized keys made of long-lasting, heat-treated S2 steel in a compact design. At home, in the studio, or on the road, D’Addario has the tools to keep you and your instrument playing their best. D'Addario is known for innovative, problem-solving, quality musical accessories offering a complete line of award-winning accessories including cables, picks, tuners, capos, straps, humidifiers, maintenance tools and more., 10-in-1 Multi-Tool, US and Metric sizes featuring:, 3 Fractional hex keys (0.05, 1/8, 3/16), 4 Metric hex keys (1.5mm, 2.5mm, 3mm, 4mm), 2 Phillips screwdrivers