From the publisher:
Ever played UNO underwater? Now you can, with UNO H20. Waterproof cards and carrying case let you take this easy, fast-paced family game to the pool, beach or anyplace that's wet.
For 2 to 10 players, Ages 7 and up
UNO H20 includes two new cards: Wild Downpour 1 and Wild Downpour 2. When played, all other players must draw 1 or 2 cards, respectively. The player of the card also determines the new color.