A free spin is essentially an offer that a casino gives to its players to spin the reels free of charge and have the opportunity to win real cash. The free spins may be given to both new and current customers, and it's one way to reward and encourage them to continue betting.
Hong Kong is a semi-autonomous city-state on the Chinese coast. A hub for Asian business, it is also known for its movie and television industry. While traditional gambling is very popular, online gambling is technically illegal. In practice, many international mobile online gambling casinos accept players from Hong Kong, and they are not actively prosecuted.