Not applicable. This is an electrical device, not a topical product.
Includes 2 x Nano Tech precision roller heads (Ultra and Fine).
Source: Scholl product information.

Charge fully before first use. Glide the roller head over dry or wet hard skin using light pressure, keeping the device moving. Do not hold it in one spot. Stop when the skin feels smooth and never file until the skin is sore. Clean the roller head and dust catcher after each use. Replace roller heads about every three months for performance and hygiene.

Two Nano Tech roller heads included: Ultra for removal, Fine for smoothing
Rechargeable, so no battery replacements
Waterproof for use in or out of the shower
Dual speed motor with a rubber easy-grip handle
Dust catcher to contain the filings

For external use on feet only. Not for use on broken, cracked, irritated or inflamed skin, or over open wounds, moles or warts. Do not over-file - remove hard skin gradually across several sessions rather than in one. Keep out of reach of children. If you have diabetes, poor circulation or reduced sensation in your feet, do not use without first speaking to your doctor or podiatrist. Discontinue use if the skin becomes sore or irritated. Follow the charging and cleaning instructions supplied with the device.