XXII. Restatement (Second) of Torts § 402A
(1) One who sells any product in a defective condition unreasonably dangerous to the user or consumer or to his property is subject to liability for physical harm thereby caused to the ultimate user or consumer, or to his property, if
(a) the seller is engaged in the business of selling such a product, and(2) The rule stated in Subsection (1) applies although
(b) it is expected to and does reach the user or consumer without substantial change in the condition in which it is sold.
(a) the seller has exercised all possible care in the preparation and sale of his product, and
(b) the user or consumer has not bought the product from or entered into any contractual relation with the seller.