This set of 7 String Super Slinky strings from Ernie Ball are the equivlent of a 6 string guitar fitted with .009s with a .052 for the 7th string. That means you get a very playable set of strings with loads of flex for bends, with a bright signature Ernie Ball Super Slinky sound you will have heard on countless recordings and stages.
Here's what Ernie Ball say about their 7 String Super Slinky strings
Ernie Ball 7 String Super Slinky Strings are widely revered for their world class tone. These strings are precision manufactured to the highest standards and most exacting specifications to ensure consistency, optimum performance, and long life. Ernie Ball 7 String Super 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 .009 .011 .016 .024w .032 .042 .052
A brief guide to strings:
The strings on your guitar have a major impact on its sound and playability. The wrong gauge makes playing harder, the guitar feel wrong and can seriously reduce your enjoyment.
Most new guitars come strung with light-gauge strings. For beginning players, that’s probably a good place to start. As you develop and your fingers gain calluses and strength, you may want to gradually move up to heavier strings, depending on the music you play.
Lighter gauge strings:
generally easier to play
allow easier bending of notes and fretting
can break more easily
produce less volume and sustain
prone to cause fret buzzing, especially on guitars with low action
exert less tension on the guitar neck and are a safe choice for vintage guitars
Heavier gauge strings:
are generally harder to play
require more finger pressure to fret and bend notes
produce more volume and sustain
are preferred for low tunings such as drop D
exert more tension on the guitar neck
Common Types of string
extra super light: .008 .010 .015 .021 .030 .038
super light: .009 .011 .016 .024 .032 .042
light: .010 .013 .017 .026 .036 .046
medium: .011 .015 .018 .026 .036 .050
heavy: .012 .016 .020 .032 .042 .054
Keep in mind that changing string gauges may require adjustments to your string height or “action” at the bridge saddles as well as adjustments to the nut and neck. Depending on your skill and the type of guitar you own, this may be better left to a guitar tech.