OPINION

A jury convicted Joe Simpson and Phillip Fisher of conspiracy to distribute and possess with intent to distribute cocaine and crack cocaine, in violation of 21 U.S.C.A. § 846 (West 1999). Simpson was sentenced to a 188-month prison term, and Fisher received a 235-month sentence. Simpson and Fisher appeal their convictions and sentences on the ground that they are invalid in light of Apprendi v. New Jersey, 530 U.S. 466, 120 S.Ct. 2348, 147 L.Ed.2d 435 (2000). Simpson also contends that the district court erred in denying his motion for judgment of acquittal under Fed.R.Crim.P. 29. Fisher asserts that the district court erred in admitting evidence of a prior conviction and that the prosecutor engaged in prosecutorial misconduct. Finding no reversible error, we affirm the convictions and sentences.

Simpson and Fisher first assert that, in light of Apprendi, their due process rights were violated because drug quantity was neither charged in the indictment nor proved to a jury beyond a reasonable doubt. We find, however, that Apprendi is not implicated because Simpson’s and Fisher’s sentences are below the 240-month statutory maximum sentence set forth in 21 U.S.C.A. § 841(b)(1)(C) (West 1999 & Supp. 2002), for drug offenses involving an unspecified amount of cocaine and crack cocaine. See United States v. Promise, 255 F.3d 150, 156-57 (4th Cir. 2001) (en banc), cert. denied, — U.S. -, 122 S.Ct. 2296, 152 L.Ed.2d 1053 (2002). Thus, their Apprendi claims fail.

Simpson also challenges his conviction on the ground that the district court erred by denying his Rule 29 motion. Our review of the record leads us to conclude that the evidence was sufficient to establish that Simpson voluntarily joined the single conspiracy charged in the indictment. United States v. Gallimore, 247 F.3d 134, 136 (4th Cir. 2001) (stating standard of review for Rule 29 motion); United States v. Burgos, 94 F.3d 849, 857-58, 862-63 (4th Cir. 1996) (en banc) (providing standard for sufficiency of evidence and elements of offense); United States v. Kennedy, 32 F.3d 876, 883 (4th Cir. 1994) (providing standard for evaluating whether material variance existed between indictment and evidence adduced at trial).

Fisher contends that the district court erred in admitting evidence, in violation of Fed.R.Evid. 404(b), that he was convicted during the course of the conspiracy of possession of a Schedule II controlled substance; that the district court’s limiting instruction was insufficient; and that the Government violated the discovery order by failing to give pretrial notice of its intention to use Fisher’s prior conviction at trial. Assuming, as Fisher suggests, that the district court improperly admitted evidence of his prior conviction, we find that any error was harmless. See United States v. Ince, 21 F.3d 576, 583 (4th Cir. 1994) (providing standard).

Finally, Fisher contends that during closing argument, the Government improperly referred to his failure to testify during closing argument. We reject his claim. See United States v. Golding, 168 F.3d 700, 702 (4th Cir. 1999) (providing standard). Even assuming that the prosecutor’s comment was improper, we find that Fisher’s substantial rights were not preju *637 diced. See United States v. Adam, 70 F.3d 776, 780 (4th Cir. 1995) (discussing factors to consider in determining prejudice).

Accordingly, we affirm Fisher’s and Simpson’s convictions and sentences. We dispense with oral argument because the facts and legal contentions are adequately presented in the materials before the court and argument would not aid the decisional process.

AFFIRMED.