N.D. Cent. Code § 35-13-03

Any person entitled to a lien under this chapter who makes, alters, or repairs more than one article of personal property for the same owner or legal possessor may include all the articles of personal property so made, altered, or repaired within ninety days, or if the property is used for agricultural purposes within one hundred twenty days, or in the exploration for or the production of oil or gas within six months, preceding the filing of the lien statement in the same statement, and the statement has the same force and effect as though a separate statement had been filed for each article.