Fashion for a good cause is even better when it’s a) practical and b) gives us the opportunity to use rubber in a headline. But on to the point. You’ve probably seen the Tretorn Wellie Wagon in one of its many stops throughout the City this spring, and you may have even picked up a new pair of rainboots or canvas sneakers from the 120-year-old Swedish footwear brand’s mobile retail unit.

 In honor of Earth Month and the Wellie Wagon’s last week in San Francisco, Tretorn is upping the ante with 25 percent off all purchases and donating $10 from every pair of newly-available white Skerry boots it sells through May 1 to the San Francisco Neighborhood Parks Council.

And though it’s looking to be a sun-filled week ahead, this year has proven the practicality of owning a good pair of rubbers. All other pairs purchased will net the Council a $1 donation. With the special discount running this week, all boots are $45 a pair.

Ready to boot up? Find the Wellie Wagon’s daily whereabouts by following @TretornSWE.