"Typically for commercials, you want a hand that isn't distracting. Nothing that would make it more notable than the product. They have a term called 'Mommy hands,' where it just looks like the classic mother doing dishes. But then [for high-end products], it's usually more about looking glamorous. They want a longer nail and fancier poses. In general, you need to have long, straight fingers. Small knuckles. Healthy nail beds, healthy nails. Usually, we have pretty long nail beds as well. Long fingernails in general."
Sometimes, their nails are the only healthy part of the picture.
Size matters, too. Doreen only models children's toys (most of those hands in ads you see during your My Little Pony marathons belong to grown women) because her hands are sufficiently dainty. "If I were to model an engagement ring, my hand would look childlike. I don't know how many viewers would pay attention to that, but, when you're making a commercial, they pay a lot of attention."