Q. What is Socket?

A.

Gear and accessory can have Socket slot in certain probability.

You can have additional abilities through Socket,

and the number of maximum Socket varies depending on the grade of the gear.

The Socket options may be unlocked with certain probability when the gear is first acquired,

and locked socket slots can be opened suing socket hammer.

After Socket open, you can chance the option by Socket change.

It requires Gold and Crystal for Socket change,

and currency needed to change the option varies depending on the grade of the item and the  number of socket slots changed.