A custom 2016 McLaren 675LT built specifically for One Drop is being auctioned off by the charitable organization in celebration of World Water Day.

The 675LT sold out within two months of being announced and, excluding the Spider variant, is limited to 500 units worldwide. The example being sold is particularly special as it was signed by McLaren Formula One driver Jenson Button while on the production line.

No pictures or further details about the car are known, including what color it is or what options it has been ordered with. Even still, the car should easily sell at auction given the ongoing demand for the hardcore variant of the popular 650S. The online auction itself has already commenced at a starting price of $400,000 and will end on March 18.

PHOTO GALLERY