Here's what Ernie Ball says about the Mega Slinky's:

MEGA SLINKY NICKEL WOUND ELECTRIC GUITAR STRINGS - 10.5-48 GAUGE
Ernie Ball Nickel Wound Electric Guitar Strings are made from nickel plated steel wire wrapped around tin plated 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 .0105, .0135, .0175, .028, .038, .048