Working for the world’s biggest technology company doesn’t mean your job will always be glamorous. As part of a batch of Earth Day 2017 videos it uploaded today, Apple expanded on something it first told Vice News Tonight last night; there’s an employee whose specialty is producing fake sweat for testing on the company’s various products.

Mostly this applies to the Apple Watch, a device that millions of people sweat on every day. In the video, Apple’s head of environmental technologies Rob Guzzo explains that he created a smaller subdivision within his team “just focused on skin safety.” And there’s good reason for that careful approach; remember when one of Fitbit’s fitness trackers gave consumers a nasty skin rash? Another employee explains the rationale: “We want to mimic actual use conditions, but we’re not going to go around collecting sweat from our employees.”

In the clip from Vice News Tonight below (hi Arielle), you’ll get a look at the real-world environmental testing lab. One thing I found interesting is that Apple puts its AirPods through this same sweat test — even though the wireless earbuds aren’t advertised as water or sweat-resistant. This isn’t unique to Apple. Garmin must have a sweat engineer. Samsung and Huawei probably do, too, and I would hope Fitbit does by now. But they haven’t (yet) given their people a rare moment in the spotlight.