Editing Tennis (section)

=== Balls ===
{{main|Tennis ball}}
[[File:Tennis Racket and Balls.jpg|thumb|A tennis racket and balls.]]

Tennis balls were originally made of cloth strips stitched together with thread and stuffed with feathers.<ref>{{cite book|last=Grimsley|first=Will|title=Tennis: Its History, People and Events: Styles of the Greats|year=1971|publisher=Prentice-Hall|location=Englewood Cliffs, New Jersey|isbn=0-13-903377-7|page=[https://archive.org/details/tennisitshistory00grim/page/14 14]|url=https://archive.org/details/tennisitshistory00grim/page/14}}</ref> Modern tennis balls are made of hollow [[vulcanized rubber]] with a [[felt]] coating. Traditionally white, the predominant colour was gradually changed to optic yellow in the latter part of the 20th century to allow for improved visibility. Tennis balls must conform to certain criteria for size, weight, [[Deformation (engineering)|deformation]], and bounce to be approved for regulation play. The International Tennis Federation (ITF) defines the official diameter as {{convert|65.41|–|68.58|mm|in|abbr=on}}. Balls must weigh between {{convert|56.0|and|59.4|g|oz|abbr=on}}.<ref name=ball>{{cite web|title=History of Rule 3 – The Ball|url=http://www.itftennis.com/technical/rules/history/index.asp#2006|publisher=ITF|access-date=1 May 2012|archive-date=6 November 2015|archive-url=https://web.archive.org/web/20151106083446/http://www.itftennis.com/technical/rules/history/index.asp#2006|url-status=dead}}</ref> Tennis balls were traditionally manufactured in the United States and Europe. Although the process of producing the balls has remained virtually unchanged for the past 100 years, the majority of manufacturing now takes place in the [[Far East]]. The relocation is due to cheaper [[labour costs]] and materials in the region.<ref>{{cite web|title=Balls- Manufacture|url=http://www.itftennis.com/technical/balls/other/manufacture.aspx|publisher=ITF|access-date=19 June 2014|archive-date=15 October 2021|archive-url=https://web.archive.org/web/20211015211603/https://www.itftennis.com/technical/balls/other/manufacture.aspx|url-status=dead}}</ref> Tournaments that are played under the ITF Rules of Tennis must use balls that are approved by the International Tennis Federation (ITF) and be named on the official ITF list of approved tennis balls.<ref name="ITF Rules">{{cite web|url=https://www.itftennis.com/media/7221/2022-rules-of-tennis-english.pdf|title=ITF Rules of Tennis|publisher=International Tennis Federation|access-date=7 November 2022}}</ref>