USA Field Hockey is the national governing body for the olympic-level sport of field hockey, both indoor and outdoor, in the United States. The Rules of Hockey at the Olympic level are issued through The Hockey Rules Board of the International Hockey Federation (FIH).
From the Field and Equipment Specificatoins,
Rule 3 Ball
3.1 The ball :
- is spherical
- has a circumference of between 224 mm and 235 mm
- weighs between 156 grams and 163 grams
- is made of any material and coloured white (or an agreed colour which contrasts with the playing surface)
- is hard with a smooth surface but indentations are permitted.
As in Outdoor Field Hockey, the ball is made of solid plastic, weighing between 5 1/2 ounces and 5 3/4 ounces with a circumference of 8 13/16 inches to 9 1/4 inches. Usually white in color, other colors may be used as agreed.
USA Field Hockey – www.teamusa.org/usa-field-hockey
International Hockey Federation – www.fih.ch/en/home
Photo – www.fmhc.org.au/category/hockey/indoor/