EB says:

Ernie Ball Power Slinky Electric Strings are a perfect match for those who like chunky rhythms for rock and roll or blues.  Power Slinkys have long been favored by Slash, Metallica, & Kenny Wayne Shepherd due to the thicker gauge combination providing a slightly more powerful tone. These strings are precision manufactured to the highest standards and most exacting specifications to ensure consistency, optimum performance, and long life. Power Slinky wound strings are made from nickel plated steel wire wrapped around a hex shaped steel core wire.  The plain strings are made of specially tempered tin plated high carbon steel; producing a well balanced tone for your guitar. Gauges .011 .014 .018p .028 .038 .048