GHS Big Core Nickel Rockers Pure Nickel Electric Guitar Strings
The reason the strings are called Big Core is because they start with a much larger core wire and then wrap around it. This offers a nice fat string that brings heavy tone and a smooth feel.

Also, the gauges are slightly different than anything else GHS offers. All sets start with half gauges (.0095, .0105) and go up from there. This gauging is of course, caused by the core wire ratio.