Kevin Purnell pled guilty to one count of possessing cocaine base with intent to distribute, in violation of 21 U.S.C. § 841(a)(1). After calculating a Guidelines imprisonment range of 188-235 months, the district court 1 sentenced Purnell to 180 months’ imprisonment. On appeal, his counsel has filed a brief under Anders v. California, 386 U.S. 738, 87 S.Ct. 1396, 18 L.Ed.2d 493 (1967), stating that Purnell believes that his sentence is substantively unreasonable.

We conclude that the district court committed no procedural error and imposed a substantively reasonable sentence. See Gall v. United States, 552 U.S. 38, 51, 128 S.Ct. 586, 169 L.Ed.2d 445 (2007) (in reviewing sentence, appellate court first *126 ensures that district court committed no significant procedural error, and then considers substantive reasonableness of sentence under abuse-of-discretion standard); United States v. Haack, 403 F.3d 997, 1004 (8th Cir. 2005) (describing abuse of discretion).

Having reviewed the record under Penson v. Ohio, 488 U.S. 75, 109 S.Ct. 346, 102 L.Ed.2d 300 (1988), we find no nonfrivolous issues. Accordingly, we allow counsel to withdraw, and we affirm.