Real Ernie Ball Slinky's (and yes you can buy "Chernie's Balls" cheaper on ebay but they are rubbish).

Ernie Ball 2221 Regular Slinky 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 Slinky: .010, .013, .017, .026, .036, .046 Super Slinky .09, .011, .016, .024, .032, .042.