The hardware store can be a fantastic place for getting toys that the kids can play with for hours!
My daughter liked working with the wrench best, it's a great lesson in patience, trying to get everything adjusted just right in little hands.
They also sorted them into the different sized nuts as they unscrewed them. They cooperated really well together and made sure each one had a job at all times. For a little bit of money, this bought me some nice quiet time!!
My children are older and do not put toys in their mouths, please be careful and watchful at all times with children when attempting this activity!