Nix Sweat Patch Refills include four single-use sweat patches to be used in conjunction with the reusable Pod before each new workout. The Sweat Patch sticks to the bicep via adhesive and is completely non-invasive. We recommend wearing a patch during a sweat inducing workout, ideally running or cycling, lasting at least 45 minutes in duration. After your run or ride is complete, a post-workout summary in the Nix App provides intel that can help inform your hydration strategy going forward.