OPINION

Andre Ashton appeals his conviction for conspiracy to distribute cocaine base, in violation of 21 U.S.C.A. §§ 841, 846 (West 2000), and his sentence to 198 months’ incarceration, sixty months’ supervised release, and a $100 special assessment. We affirm.

We must affirm Ashton’s jury convictions if there is substantial evidence, when viewed in the light most favorable to the Government, to support the jury’s verdict. Glasser v. United States, 315 U.S. 60, 80, 62 S.Ct. 457, 86 L.Ed. 680 (1942). In determining whether the evidence is substantial, we view the evidence in the light most favorable to the Government and inquire whether there is evidence sufficient to support a finding of guilt beyond a reasonable doubt. United States v. Burgos, 94 F.3d 849, 862 (4th Cir. 1996).

The evidence showed Ashton conspired with Damon Gilchrist and James Braun in distributing crack cocaine over a six to seven month period. The jury was made aware through direct and cross examinations of the witnesses’ prior criminal records, hopes for some future benefit, and histories of substance abuse, and assessed the witnesses’ credibility accordingly, which was within the sole province of the jury and is not susceptible to judicial review. See United States v. Lowe, 65 F.3d 1137, 1142 (4th Cir. 1995). Phone records further corroborated the existence of a conspiracy. We affirm Ashton’s conviction, finding it was based upon substantial evidence.

We further affirm Ashton’s sentence, which was within the statutory maximum and not in violation of the Supreme Court’s ruling in Apprendi v. New Jersey, 530 U.S. *191 466, 120 S.Ct. 2348, 147 L.Ed.2d 435 (2000). See United States v. Promise, 255 F.3d 150 (4th Cir. 2001); United States v. Kinter, 235 F.3d 192, 201 (4th Cir. 2000), cert. denied, — U.S.-, 121 S.Ct. 1393, 149 L.Ed.2d 316 (2001). We find the district court sufficiently specified its finding of the drug quantity and type, which was adequately supported by a preponderance of the evidence. See United States v. Angle, 254 F.3d 514 (4th Cir. 2001) (en banc), cert. denied, — U.S.-, 122 S.Ct. 309, — L.Ed.2d-(2001). We grant Ash-ton’s motion to file a pro se supplemental brief and have considered and reject the Apprendi claim raised therein. 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 in the decisional process.

AFFIRMED.