Israel Solano appeals the sentence the district court imposed upon his guilty plea to a conspiracy involving drug trafficking. On appeal, counsel has moved to withdraw and filed a brief pursuant to Anders v. California, 386 U.S. 738, 87 S.Ct. 1396, 18 L.Ed.2d 493 (1967), in which he argues Solano’s stipulation to his total offense level was not knowing and voluntary. Solano assured the district court judge in open court that he understood the stipulation, that he already had an adequate opportunity to discuss it with counsel, and that he wanted to be bound by the stipulation. We conclude the stipulation was voluntary. See United States v. Stalder, 696 F.2d 59, 62 (8th Cir. 1982); cf. Blackledge v. Allison, 431 U.S. 63, 74, 97 S.Ct. 1621, 52 L.Ed.2d 136 (1977) (holding that declarations in open court carry a strong presumption of truth). Thus, Solano cannot now challenge his total offense level on appeal. See United States v. Hawkins, 215 F.3d 858, 860 (8th Cir.), cert, denied, 531 U.S. 972, 121 S.Ct. 414, 148 L.Ed.2d 319 (2000); United States v. Nguyen, 46 F.3d 781, 783 (8th Cir. 1995).

We have reviewed the record in accordance with Penson v. Ohio, 488 U.S. 75, 109 S.Ct. 346, 102 L.Ed.2d 300 (1988), and find no nonfrivolous issues. Accordingly, we affirm and grant counsel’s motion to withdraw.