38 C.F.R. § 20.605
If it appears during the course of a hearing that additional evidence would assist in the review of the questions at issue, the presiding Member may direct that the record be left open so that the appellant and his or her representative may obtain the desired evidence. The presiding Member will determine the period of time during which the record will stay open, considering the amount of time estimated by the appellant or representative as needed to obtain the evidence and other factors adduced during the hearing. Ordinarily, the period will not exceed 60 days, and will be as short as possible in order that appellate consideration of the case not be unnecessarily delayed.
38 C.F.R. §20.605
Authority: 38 U.S.C. 7102 ; 38 U.S.C. 7105 , 7101 (2016)