Stunt kites (or Sport kites) are dual-lines steerable kites and have roughly triangular "delta" shape. The very basic aspects of flying and kite designs are: all-around kites; precision & "ballet"; low wind/indoor; trick/competition kites; speed & power!
To control the kite, the pilot pulls on the right hand line to turn right, left line to turn left, and so on. The pitch can sometimes be controlled by walking/running forward or backwards, giving the lines different amounts of tension. Using a combination of pulls and pushes (to give slack to the lines), complex tricks and patterns can be flown. These range in difficulty from turns, loops and landings, to maneuvers where the kite is flipped and turned end over end, wrapping the lines or floating on its front or back. During diving maneuvers or crossing the power zone, sport kites may reach a speed of 100km/h. The high speed is not a goal (except for power deltas) and could be dangers in some cases. When the kite is not flying forwards or sinking downwards (with nose pointed up) it's actually stalled. Mastering the stall is a key to learning basic tricks like axels and 540s.
Sport kites can be designed to fly in a wide range of conditions. Most standard kites fly best in wind ranges 2-4bft (10-25km/h). High wind kites can be flown in very strong winds, up to 7-8bft (~70km/h). There are kites made from the lightest materials that can be flown in the slightest breeze or even indoors. For smooth and consistent flying, a steady breeze is required, uninhibited by trees, buildings, hills, or other tall objects which may cause turbulences. It's hard to fly in turbulent wind conditions and almost impossible to perform nice and graceful tricks and maneuvers.
A dual line stunt kite can range from anywhere from 20 euro for a beginner kite, to over 300 euro for specialized competition kites made from high grade materials such as carbon fiber and Mylar. Almost every performance trick kite has optional tail weight attachments, which change the flight characteristics of the kite, making some advanced maneuvers easier or more dramatic. The lines are made from Dyneema , which is light, doesn't stretch and stays slippery even when wrapped many times.