In Underwater Hockey
An underwater hockey puck (originally but now rarely referred to as a "squid" in the United Kingdom), while similar in appearance to an ice hockey puck, differs in that it has a lead core weighing approximately 3 pounds (1.4 kg) within a teflon, plastic or rubber coating. This makes the puck dense enough to sink in a swimming pool, though it can be lofted during passes, while affording some protection to the pool tiles.
A smaller and lighter version of the standard puck exists for junior competition and is approximately 1 lb 12 oz (0.80–0.85 kg) and of similar construction to the standard puck.
While there are numerous regional variations in colour, construction and materials all must conform to international regulations stipulating overall dimensions and weight. The regulations state that pucks should be a bright distinctive colour, for example high-visibility pink or orange, and that for World Championships these are the only acceptable colours. The relevant regulations can be found within the Official Rules at www.thewaa.org
Read more about this topic: Hockey Puck