PER CURIAM.

Defendant-Appellant William Berr?os-Cruz appeals certain special conditions of supervised release imposed in connection with his guilty plea to production of child pornography. See 18 U.S.C. ? 2251(a). Because Berr?os’s plea agreement contained a knowing and voluntary waiver of any right to appeal his sentence, we may reach the merits of his claims only to prevent a “miscarriage of justice.” United States v. V?lez-Luciano,?814 F.3d 553, 559 (1st Cir. 2016). With respect to all but one of the challenged conditions, Berr?os falls short of this bar and, accordingly, we must enforce his appellate waiver.

Condition four’s requirement that Berr?os submit to penile plethysmograph (“PPG”) testing, however, presents a different situation. Indeed, the government concedes that this requirement, imposed without any explanation by the district court, should be vacated. See United States v. Medina,?779 F.3d 55, 71 (1st Cir. 2015) (holding that the district court must “provide a substantial justification before making submission to PPG testing part of a condition of supervised release”). We agree that enforcement of Berr?os’s appellate waiver with respect to the PPG testing requirement would result in a miscarriage of justice. See V?lez-Luciano, 814 F.3d at 564-65 (holding that “potentially subjecting [the defendant] to PPG testing when the government expressly disavows the utility of this particular procedure about which we have expressed reservations, especially when the record lacks any explanation of the applicability of PPG testing to this defendant, constitutes a miscarriage of justice,” as well as plain error (citation omitted)).

For the foregoing reasons, we VACATE the portion of condition four that authorizes PPG testing and remand for the district court to consider the parties’ joint recommendation that the relevant part of the condition be stricken. We AFFIRM all other aspects of Berr?os’s sentence.