Steven Cory pleaded guilty to conspiring to sell drug paraphernalia, in violation of 21 U.S.C. § 846, and a forfeiture count. After granting the government’s substantial-assistance departure motion, the district court 1 sentenced him to 21 months imprisonment and 1 year supervised release. On appeal, counsel has moved to withdraw and filed a brief under Anders v. California, 386 U.S. 738, 87 S.Ct. 1396, 18 L.Ed.2d 493 (1967), arguing the district court erred by failing to state the reasons for Cory’s sentence, thereby precluding meaningful appellate review of the extent of the downward departure.

We conclude that Cory waived this argument because he did not raise it below. See United, States v. McCabe, 270 F.3d 588, 590 (8th Cir. 2001), cert, denied, — U.S.-, 122 S.Ct. 1588, 152 L.Ed.2d 506 (2002). Further, any error did not affect Cory’s substantial rights and therefore is harmless, because the extent of the downward departure is unreviewable. See Fed. R.Crim.P. 52(a); United States v. Puckett, 147 F.3d 765, 772 (8th Cir. 1998). Finally, following our independent review, see Penson v. Ohio, 488 U.S. 75,109 S.Ct. 346,102 L.Ed.2d 300 (1988), we find no nonfrivolous issues.

Accordingly, we grant counsel’s motion to withdraw, and we affirm.