Kim, Khloe and Kourtney Kardashian are auctioning off a one-of-a-kind autographed t-shirt to support the NOH8 Campaign, which raises awareness and funds for gay rights causes, including ending California's 2008 voter-approved gay marriage ban, Proposition 8.

The co-stars of E!'s reality series Keeping Up with the Kardashians were early supporters of the campaign.

The 7-day auction on Ebay racked up 54 bids on its opening day.

In addition to the t-shirt, which reads “All [heart] NOH8,” the auction includes the women's official NOH8 portraits.

“All proceeds from this special auction will go to the NOH8 Campaign,” the group said in announcing the auction. “[S]o help get the word out about this special auction! Funds raised by the NOH8 Campaign will be used to continue promoting and raising awareness for marriage equality and anti-discrimination through NOH8's interactive media campaign.”

NOH8 Campaign founders Adam Bouska and Jeff Parshley photograph celebrities and everyday folks with their mouths duct taped and the campaign's familiar “NOH8” slogan often written on one cheek. Proceeds from the photographs support gay rights causes.