Bowls or lawn bowls is a sport in which the objective is to roll biased balls so that they stop close to a smaller ball.
According to the Corporate Challenge Lawn Bowls – Basic Rules, The bowls are all colour coordinated and different colours relate to different sizes. The colour of the bowls in increasing size are:
Blue –smallest (suitable for women)
Green (suitable for women)
Red (suitable for women)
Red & White
Blue & White (largest)
References:
Rules – http://www.amcs.ymca.org.au/Media/docs/Lawn-Bowls-Introduction-Basic-Rules-MASTER-35788d9c-35e5-4224-b2ed-be84ae4feb5e-0.pdf
Photo – http://www.hklba.org/new/index.php?option=com_content&view=category&layout=blog&id=46&Itemid=45&lang=en