This is a two-sided foot file with a wood handle, made by Silkline for callus removal and heel smoothing. One side is a coarse grain meant for use on dry skin, breaking down thick calluses; the other is a finer grain meant for use on wet, softened skin, finishing the heel to a smoother, even texture.
It's a manual, reusable file rather than a single-use disposable. The manufacturer notes it's sanitizable with a chemical sterilizer between uses, standard practice in professional pedicure settings, and rates it as durable for roughly three months of regular use before the abrasive surface wears down. That makes it a consumable tool rather than a permanent one, similar to a standard nail file.
Use it for maintenance between pedicures at home, or as a standard part of a professional pedicure setup. We can't confirm any antibacterial property in the material itself, so that claim isn't repeated here; sanitizing between uses with a proper disinfectant is what actually keeps it hygienic.