What does Morris give to Mr. White in "The Monkey's Paw"?

Morris gives Mr. White a magical monkey’s paw that grants three wishes.

It is a dark and stormy night when the White family is visited by an old friend, Sergeant-Major Morris.  He brings with him a little trinket, which he says has magical powers. 

"Well, it's just a bit of what you might call magic, perhaps," said the sergeant-major off-handedly. …   "It had a spell put on it by an old fakir," said the sergeant-major .... He put a spell on it so that three separate men could each have three wishes from it."

The Whites are interested, but they mostly think this is just a story told for entertainment.  Morris throws the paw in the fire, and tells Mr. White that if he is sensible he will leave it there.  White asks him how it works, and he explains that you wish on it.

Herbert White, White’s son, convinces him to wish for money.  He does not take it seriously either, but thinks it will be fun.  Mr. White says he doesn’t really need anything, but makes the wish anyway.

"If the tale about the monkey paw is not more truthful than those he has been telling us," said Herbert, as the door closed behind their guest, just in time for him to catch the last train, "we shan't make much out of it."

The paw turns out to be real.  The Whites find this out only when they get a knock at the door telling them that their son is dead.  They get the money they wished for, but at great cost.  Grieving, Mrs. White wishes for her son to be alive again.  However, it has been ten days, and Mr. White is worried about the state their son will be in.  They hear a knocking at the door after a while. Horrified, Mr. White wishes to undo their wish. The knocking stops.