N.J. Stat. § 19:7-2
A candidate who has filed a petition for an office to be voted for at the primary election, and a candidate for an office whose name may appear upon the ballot to be used in any election, may also act as a challenger as herein provided and may likewise appoint 2 challengers for each district in which he is to be voted for; but only 2 challengers shall be allowed for each election district to represent all the candidates nominated in and by the same original petition. The appointment of the challengers shall be in writing under the hand of the person or persons making same and shall specify the names and residences of the challengers and the election districts for which they are severally appointed. Whenever a public question shall appear on the ballot to be voted upon by the voters of an election district and application has been made by the proponents or opponents of such public question for the appointment of challengers, the county board may in its discretion appoint 2 challengers each to represent such proponents or opponents. Such challengers shall be in addition to those provided for in section 19:7-1 of this Title.
N.J.S. § 19:7-2