Simplify the following text for a Grade 4 native English-speaking person.
Original: A standard ice hockey puck is black , 1 i thick , 3 i in diameter , and weighs between 5.5 a ; some pucks are heavier or lighter than standard ( see below ) .
Simplified: Hockey pucks are hard disks of rubber that are used to play ice hockey . A standard ice hockey puck is black , 1 inch thick ( 25.4 mm ) , 3 inches in diameter ( 76.2 mm ) , and weighs between 5.5 and 6 ounces ( 156-170 g ) .