Editing Polo (section)

=== Ball ===
The modern outdoor polo ball is made of a high-impact plastic. Historically they have been made of [[bamboo]], leather covered [[Cork (material)|cork]], hard rubber, and for many years willow root. Originally the British used a white painted leather covered cricket ball.<ref>{{cite book|last1=Laffaye|first1=Horace A.|title=The polo encyclopedia|date=2004|publisher=McFarland|location=Jefferson, N.C.|isbn=0-7864-1724-2|page=28}}</ref>

The regulation outdoor polo ball is {{convert|3|in|cm}} to {{convert|3+1/2|in|cm}} in diameter and weighs {{convert|3+1/2|oz|g}} to {{convert|4+1/2|oz|g}}.<ref>{{cite book|title=Rules and Rule Interpretations of the United States Polo Association |publisher=United States Polo Association |page=64 |date=2017 |url=https://www.uspolo.org/assets/docs/2017-USPA-Rulebook-web.pdf |access-date=9 November 2017|archive-url=https://web.archive.org/web/20171109023557/https://www.uspolo.org/assets/docs/2017-USPA-Rulebook-web.pdf |archive-date=9 November 2017 |url-status=dead}}</ref>

Plastic balls were introduced in the 1970s. They are less prone to breakage and much cheaper.<ref>{{cite web|title=Outdoor Polo Ball |url=http://www.worldpolonews.com/2015/outdoor-polo-ball/|website=World Polo News|access-date=9 November 2017|date=7 October 2015|archive-url=https://web.archive.org/web/20171109081050/http://www.worldpolonews.com/2015/outdoor-polo-ball/|archive-date=9 November 2017|url-status=dead}}</ref>

The indoor and arena polo ball is leather-covered and inflated, and is about {{convert|4+1/2|in|cm}} in diameter.{{citation needed|date=September 2022}}

It must be not less than {{convert|12.5|in|cm}} or more than {{convert|15|in|cm}} in circumference. The weight must be not less than {{convert|170|g|oz}} or more than {{convert|182|g|oz}}. In a bounce test from {{convert|9|ft|m}} on concrete at {{convert|70|°F|°C}}, the rebound should be a minimum of {{convert|54|in|cm}} and a maximum of {{convert|64|in|cm}} at the inflation rate specified by the manufacturer. This provides for a hard and lively ball.{{citation needed|date=September 2022}}