It’s 2017, why are you still working out in cotton? C’mon! We’ve sung the praises of merino many times before, but today Los Angeles-based athletic apparel brand Olivers is giving us a new reason to do so. Their newly launched Ditch the Dry-Fit initiative is offering customers a nice rebate when they upgrade their kit by purchasing a new Terminal Tech shirt and sending in an old synthetic workout tee.

The Terminal material is a poly blend of merino mesh that’s naturally odor resistant and moisture wicking, making it great for everything from hitting the gym to commuting and general travel. The slim cut makes it applicable as an undershirt during colder months too. And the double knit construction ensures longevity.

But back to the initiative. How does it work? First, you purchase a new Tee. Then, you package up your old synthetic workout shirt, and send it to Olivers LA HQ. Oliver will then issue you a $25 refund on your original order. And at the end of the month (the initiative runs through the end of July) the Olivers team will wash all the donations and find new homes for them through work with Back on My Feet, a nonprofit that specializes in fighting homelessness through running and employment programs.