Sean Lewis directly appeals the district court’s 1 judgment entered after he pled guilty to conspiracy to distribute a heroin, in violation of 21 U.S.C. §§ 841(a)(1), (b)(1)(C), and 846, and to being a felon in possession of firearms and ammunition, in violation of 18 U.S.C. §§ 922(g)(1) and 924(a)(2). Following careful review of the arguments raised in the brief filed by Lewis's counsel pursuant to Anders v. California, 386 U.S. 738, 87 S.Ct. 1396, 18 L.Ed.2d 493 (1967), we conclude (1) the district court’s findings with regard to the drug-quantity attribution and application of the aggravating-role, vulnerable-individual, and obstruction-of-justice adjustments were supported by the testimony at the sentencing hearing and were not clearly erroneous; (2) the determination that Lewis was a career offender did not affect his sentence; and (3) his sentence was not substantively unreasonable. Turning to Lewis’s pro se arguments, we find no error, plain or otherwise, with regard to application of the sentencing enhancement for his possession of a firearm, and no breach of the plea agreement by the government. Finally, having independently reviewed the record pursuant to Penson v. Ohio, 488 U.S. 75, 109 S.Ct. 346, 102 L.Ed.2d 300 (1988), we have found no non-frivolous issues for appeal. The judgment of the district court is affirmed, 2 and counsel’s motion to withdraw is granted.