How did the gray women help perseus?

The Gray Women, also known as the Graeae, assisted Perseus by providing him with vital information needed to locate the Gorgon Medusa. They were three sisters who shared one eye and one tooth among them, and Perseus forcibly took their eye as leverage. By threatening to keep it until they revealed the location of the nymphs who possessed the magical items he needed, Perseus was able to obtain directions to find the nymphs and ultimately his goal of defeating Medusa.