N.J. Stat. § 51:1-101: Presence of weights, etc., presumptive evidence of use

Proof of the existence of weights or measures in or about any place or vehicle, in or from which it is shown trade is commonly carried on shall be presumptive evidence of their regular use for such purpose and of their ownership by the person so using or possessing them and such facts shall be deemed to remain established until disproved beyond reasonable doubt.