Earlier in June 2019, legendary Pink Floyd guitarist and songwriter David Gilmour auctioned off dozens of his guitars and sold them all so that he could donate the proceeds to charity.

Gilmour auctioned off 126 of his guitars at Christie’s, raking in a total of $21 million.

The most remarkable guitar to hit the auctioneer’s block was the iconic black Stratocaster that Gilmour used to record “Comfortably Numb,” “Shine on You Crazy Diamond,” and “Money,” as Guitar World reports.

The ax ended up fetching a hefty $4 million after the owner of the Indianapolis Colts purchased it.

The English rock star says that he’ll be donating every penny of the auction’s sales to nonprofit environmental ClientEarth.

“The global climate crisis is the greatest challenge that humanity will ever face, and we are within a few years of the effects of global warming being irreversible,” Gilmour tweeted.

Watch Gilmour’s video announcement below: