Marshall Box appeals the 144-month sentence the district court 1 imposed after granting the government’s post-judgment Federal Rule of Criminal Procedure 35(b) motion to reduce Box’s sentence based on substantial assistance. Box’s counsel has moved to withdraw and has filed a brief under Anders v. California, 386 U.S. 738, 87 S.Ct. 1396, 18 L.Ed.2d 493 (1967), arguing that Box’s cooperation, age, and other factors warranted a 50-60% sentence reduction rather than the lower reduction the district court applied. Counsel’s argument is unavailing. See United States v. Haskins, 479 F.3d 955, 957 (8th Cir. 2007) (per curiam) (court lacks jurisdiction to consider reasonableness of sentence following Rule 35(b) reduction; United States v. Booker, 543 U.S. 220, 125 S.Ct. 738, 160 L.Ed.2d 621 (2005), did not expand 18 U.S.C. § 3742(a) to include appellate review of discretionary sentencing reductions); United States v. Coppedge, 135 F.3d 598, 599 (8th Cir. 1998) (per curiam) (challenge to extent of sentence reduction upon government’s Rule 35(b) motion was unreviewable because appeal was not based on any criteria listed in § 3742(a)).

Having reviewed the record independently under Penson v. Ohio, 488 U.S. 75, 80, 109 S.Ct. 346, 102 L.Ed.2d 300 (1988), we find no nonfrivolous issues. According *617 ly, we grant counsel’s motion to withdraw, and we affirm.