Geezer Butler attends the 2023 Last Chance For Animals Gala at The Beverly Hilton on October 14, 2023 in Beverly Hills, California. (Unique Nicole/Getty Images)

Gear used by Black Sabbath bassist Geezer Butler is going up for sale.

Fifteen hand-signed Hand of Doom amp heads will be available for purchase via the online gear marketplace Reverb.

“This is your chance to own the sound that defined heavy metal,” reads a post to the Reverb website. “Don’t wait, once they’re gone, they’re gone.”

You can sign up now for email alerts for when the amps go on sale via Reverb.com.

Butler performed with his original Black Sabbath bandmates — Ozzy Osbourne, Tony Iommi and Bill Ward — for the last time at the Back to the Beginning concert, held July 5 in the band’s hometown of Birmingham, England. Ozzy died just over two weeks later on July 22.