Pink Floyd guitarist David Gilmour sold over 120 of his guitars for a charity that combats climate change.

According to NBC News, the former frontman’s auction raked in $21.5 million, all of which will be donated to ClientEarth, a nonprofit environmental law organization that prides itself on using the law to "combat climate change” and “defend habitats and wildlife," according to its Facebook page.

Gilmour tweeted about his decision to sell the guitars on Friday, writing, “The choice really is that simple, and I hope that the sale of these guitars will help ClientEarth in their cause to use the law to bring about real change.”

“We need a civilized world that goes on for all our grandchildren and beyond in which these guitars can be played and songs can be sung,” he wrote, adding that 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.”

Christie's auction house told NBC News that Gilmour’s auction was the largest sale of guitars ever sold at auction. 

One of the 126 items sold at the auction was Gilmour’s "Black Strat" guitar, which he reportedly used to record “Dark Side of the Moon.” The item was expected to sell for around $150,000, but ended up selling for almost $4 million.