Crystals can not only be bought or received in battles but you can also get them inviting friends to the game. Besides you constantly receive crystals not only for the fact of your friends‘ registration but for their progress and achievements.
Window „Invite a friend“ opens with pressing special button:
There are 3 ways to invite friends: sending invitations letters via E-mail, getting a link to send invitations (e.g. via ICQ) and getting a banner which can be placed at your site or blog.
Your current tank, your name, points and rate position will be visible on the banner.
Statistics of friends registered through your link can be viewed in the window „Invite a friend“, section „Invitation statistics“.