Brand from Japan: Kowa. Innovative nail care that strengthens the nails themselves.A highly functional medical nail liquid that penetrates thin nails, nails that are prone to brittle, and weak nails to repair damage from the inside. Unlike general nail oils and hardeners, the ingredients penetrate deep into the nail and act directly on the nail itself to repair and strengthen it.How to use:Please apply to natural nails that are not covered with nail polish. It is not effective if applied over nail polish. It is possible to apply it to the underside of the tip of the nail, but the liquid will not spread over the entire nail. It only works on the area where it is applied. It is easily washed away by water, so we recommend using it before going to bed. Assuming you apply it to both hands once a day before going to bed, it will last for approximately 30 to 40 days.