Refer to Section 402A of the Restatement (Second) of Torts: What does "the seller is engaged in the business of selling such a product" mean? Who is excluded by this? What does "it is expected to and does reach the user or consumer without substantial change in the condition in which it is sold" mean? What situation does this cover? What is the difference between the idea that the rule applies although "the seller has exercised all possible care in the preparation and sale of his product" and the rule of negligence? What does "the user or consumer has not bought the product from or entered into any contractual relation with the seller" mean?