Audemars Piguet has a unique Royal Oak hitting the auction block that will be supporting a great cause, the One Drop Foundation, who helps bring sustainable access to clean water around the world. The foundation has teamed up with the watchmaker to create a one-off 41mm Royal Oakey with a stunning Grande Tapisserie dial in deep purple and is in encased in platinum with a matching platinum bracelet. It also includes a blue alligator leather strap. 

$112,000 (estimated value), audemarspiguet.com