The Razor of Hair-growth

A mage has taught his students many things, about the ways of a true wizard. But he often loudly admired a certain quality that few wizards have, and is rarely recognized: the art to create new original magical items, that were simple in making and could be easily sold, thus promoting the usefulness of magic, and becoming rich this way.

One student had enough of his laments one day, and devised a useless prank item (knowing the mage's vanity and wont of a clean, shaved face). When the truth was discovered, the mage was quite enraged. But to his student's dismay, he saw the possibilities...

...and is selling these razors until today.

Magical Properties:

In the act of shaving, the razor stimulates the shaved area to grow more bodily hair, faster and bigger.

Uses:
- Obviously, for pranks. It takes some time to notice, but the growth accelerates, and the victim has to shave more often, likely with the same razor. May be particularly cruel if used to spoil female beauty. (Does not apply to hobbit wiwes though...) Some would call it cursed.
- Curing baldness. Unless the head is completely bare and devoid of any hair, shaving it may 'wake up' anything that remains, and initiate the growth of new hair. This particular use can bring much gold from the vain and unlucky.
- Raising your manliness! If you desire a nice manly hairy chest, go ahead.
- A relatively slow (taking weeks) but effective disguise. Will grow a nice beard in relatively short time.
- A farmer has begun with experiments on sheep, desiring better and longer wool. This may bring the biggest economical effect over time.

Limits:
First, the effect is limited in time. Regular shaving can prolong it to weeks or even months, but certainly not longer. The bodily hair in question will grow into the new length, but the acceleration will steadily slow down (unless shaved again with this razor).

Second and more important, this is a very weak magic item. It does not create anything new, it just makes a certain natural process faster (though it may support the growth of new hair). A beard would stay even on a child, but would probably not regrow if later removed with ordinary items. The process will never speed up beyond natural limits (shaven asleep, wake up with a full dwarwen beard).