Mark Ruffalo is a movie star, a political and environmental activist, and — in a move that combines those two pursuits — now a T-shirt entrepreneur.

The actor tweeted out the link Monday for an officially licensed, limited-edition Avengers shirt intended to raise money for the Solutions Project. Ruffalo cofounded the organization in 2011, which works to speed the move to 100 percent renewable energy in the United States.

To help promote the shirt — which is available as a tee, a long-sleeve shirt, and a fleece — Ruffalo enlisted his fellow Avengers Chris Hemsworth and Scarlett Johansson to model the look. The garment is a fetching mix of old- and new-school, with the original six cinematic Avengers depicted with a certain retro flair. It is the considered opinion of Inverse that this is, as superhero shirts go, a good shirt.

The main focus of the Solutions Project is the 100% Campaign, which both encourages American cities and towns to pledge to make the shift to fully renewable energy and organizes events to raise awareness about the need to abandon fossil fuels. The organization also offers grants for individuals and community groups to help them fight climate change and develop clean energy at a local level.

So far, 681 shirts have been sold, raising between $20,000 and $25,000 for the cause, minus production costs. The shirts will be available to purchase here through December 31, though those looking to give this as a last-minute holiday gift be warned: The shirts don’t actually ship until January 16. So maybe print out this photo of Chris Hemsworth in the meantime.

Along with Ruffalo, the founders of the Solutions Project are Mark Z. Jacobson, the director of Stanford University’s Atmosphere/Energy Program; Josh Fox, the maker of the anti-fracking documentary Gasland; and Marco Krapels, a renewable energy executive.

A key principle of the group is based on Jacobson’s academic research that the United States can maintain a stable electrical grid without any reliance whatsoever on non-renewable energy sources like fossil fuels. TAnother tenet is that the tech to make the switch to solar and other clean energy sources is already in place, and it’s just a question of making American society and politics more open to renewables.

That’s where Ruffalo — and his Avengers shirts — enter the picture, even if the garment opts for an “I Still Believe in Heroes” slogan instead of some direct environmental advocacy. You know, something like “The Real Avengers are Solar and Wind Power.” Yeah, we’re starting to see why they went with what they did.