Quads is poker slang for four of a kind: four cards of the same rank, such as four queens, plus one unrelated card, the kicker. In standard hand rankings, quads beat a full house and every hand below it, and lose only to a straight flush, of which the royal flush is the highest. When two players both hold four of a kind, the higher rank wins.
Because the hand is so rare, it features in many poker promotions; bad-beat jackpots, for example, often require four of a kind or better to lose. In video poker, four of a kind is a key line on the paytable, and some variants pay extra for particular ranks, such as four aces. Operators listing video poker or poker side-bet games should check how each title ranks and pays the hand.