Roller hockey is a form of hockey played on a dry surface using wheeled skates. The term "Roller hockey" is often used interchangeably to refer to three variant forms chiefly differentiated by the equipment used: traditional "Roller hockey" (Quad hockey, Rink hockey), played with quad skates and a ball (without contact), "Inline hockey", played with inline skates and puck (without contact) and "Skater hockey", played with quad skates or inline skates and plastic ball (with contact like ice hockey). Most professional inline hockey games take place on an indoor or outdoor sport court (a type of plastic interlinking tiles used to create a skating surface). Otherwise, any dry surface can be used to host a game, typically a roller rink, macadam, or cement. Combined, roller hockey is played in nearly 60 countries worldwide.