A written statement provided by a party upon demand setting forth the specific facts that support the claims, damages, or defenses asserted in the action. The purpose of the bill of particulars is to shed light on the specific matters in issue, amplify the pleadings, limit the proof, and prevent surprise at trial. The party on whom the demand is made must serve a bill of particulars within 30 days answering each item of the demand, except any item to which the party objects. If the party objects to an item, it must state the reasons for the objection with reasonable particularity (CPLR 3042(a).)