Fusskraft Herbal Bath is a foot-soak salt from Gehwol combining urea with camphor, lavender, rosemary, mountain pine and thyme oils, meant to be dissolved in warm water for a foot bath that helps with odor, perspiration and softening rough or calloused skin.
Gehwol's own directions for dosing this soak vary across sources, so rather than state one precise measurement, we'd recommend following the dosing on your package and adjusting to preference — a typical soak is 10–15 minutes in warm water.
It works well as a pre-treatment before a foot cream, since a soak followed by a cream tends to be more effective than either step alone.