Not applicable. This is a device accessory, not a topical product.
Contains 2 roller heads.
Source: Scholl product information.

Remove the used roller head from the device and fit the replacement until it clicks into place. Clean after each use. Replace about every three months.

Two replacement roller heads per pack
Removes very hard skin
Can be used wet or dry
Roughly six months of ordinary use
Change every three months for performance and hygiene

For use with Scholl ExpertCare electronic foot files only. Keep out of reach of children. For external use on feet. Not for use on broken, cracked or irritated skin, or over open wounds, moles or warts. If you have diabetes, poor circulation or reduced sensation in your feet, do not use without first speaking to your doctor or podiatrist.