last longer. Properly humidified feathers flex during play, enhancing the shuttle's speed change and durability. Dry feathers are brittle and break easily, causing the shuttle to wobble. Saturated feathers are 'mushy', making the feather cone narrow too much when strongly hit, which causes the shuttle to fly overly far and fast. Typically a humidification box is used, or a small moist sponge is inserted in the feather end of the closed shuttle tube container, avoiding any water contact with the cork of the shuttle. Shuttles are tested prior to play to make sure they fly true and at the proper speed, and cover the proper distance. Different weights of shuttles are used to compensate for local atmospheric conditions. Both humidity and height above sea level affect shuttle flight. World Badminton Federation Rules say the shuttle should reach the far doubles service line plus or minus half the width of the tram. According to manufacturers proper shuttle will generally travel from the back line of the court to just short of the long doubles service line on the opposite side of the net, with a full underhand hit from an average player. The cost of good quality feathers is similar to that of good quality plastics, but plastics are far more durable, typically lasting many matches without any impairment to their flight. Feather shuttles are easily damaged and should be replaced every three or four games or sooner if they are damaged and do not fly straight. Damaged shuttles interfere with play as any impairment may misdirect the flight of the shuttlecock. Most experienced and skillful players greatly prefer feathers, and serious tournaments or leagues are always played using feather shuttlecocks of the highest quality. The playing characteristics of plastics and feathers are substantially different. Plastics fly more slowly on initial impact, but slow down less towards the end of their flight. While feathers tend to drop straight down on a clear shot, plastics never quite return to a straight drop, falling more on a diagonal. Feather shuttles may come off the strings at speeds in excess of 320 km/h (200 mph) but slow down faster as they drop. See also Jianzi – a traditional Asian game in which players aim to keep a heavily weighted shuttlecock (Jian) from touching the ground Battledore and shuttlecock – an ancient game similar to that of modern badminton References External links Badminton equipment Racket