Final answer:
Cuticle oil aids in moisturizing brittle nails by nourishing and hydrating the nail bed.
Step-by-step explanation:
The product that aids in moisturizing brittle nails is cuticle oil. Cuticle oil helps to nourish and hydrate the nail bed, which can improve the overall health and strength of the nails. It is applied to the cuticles and massaged in to promote moisture retention.