New Jersey Statutes Title 2C. The New Jersey Code of Criminal Justice 2C § 39-9.1

A person who sells any hunting, fishing, combat or survival knife having a blade length of five inches or more or an overall length of 10 inches or more to a person under 18 years of age commits a crime of the fourth degree; except that the establishment by a preponderance of the evidence of all of the following facts by a person making the sale shall constitute an affirmative defense to any prosecution therefor: a. that the purchaser falsely represented his age by producing a driver's license bearing a photograph of the licensee, or by producing a photographic identification card issued pursuant to section 2 of P.L.1980, c. 47 (C.39:3-29.3), or by producing a similar card purporting to be a valid identification card indicating that he was 18 years of age or older, and b. that the appearance of the purchaser was such that an ordinary prudent person would believe him to be 18 years of age or older, and c. that the sale was made in good faith relying upon the indicators of age listed in a. and b. above.