The Power Wound electric guitar strings are made with a nickel-plated cover wrap over a hard-tempered hex core. These strings are a perfect combination of brightness and longevity. Most importantly, these strings will Stay-In-Tune. This S1150 set comes with both a PLAIN and WOUND third so you can chose according to your preference. Gauges 11-15-18P (and 20W)-26W-36W-50W