Tyree L. Lampkin appeals the sentence the district court 1 imposed after he pleaded guilty to conspiring to distribute and possess with intent to distribute 50 grams or more of a mixture or substance containing cocaine base, in violation of 21 U.S.C. § 846. Mr. Lampkin contests the amount of cocaine base the court attributed to him at sentencing. See U.S.S.G. § 2D1.1(c)(1). The government bears the burden of establishing by a preponderance of the evidence both the type and quantity of drugs attributable to a defendant, and we “will reverse only if firmly convinced a mistake has been made.” See United States v. Thompson, 335 F.3d 782, 784 (8th Cir. 2003) (type), cert. denied, — U.S. -, 124 S.Ct. 1111, 157 L.Ed.2d 940 (2004); United States v. Sarabio-Martinez, 276 F.3d 447, 450 (8th Cir. 2002) (quantity). After carefully reviewing the record, including the sentencing testimony of various witnesses who described drug transactions involving Mr. Lampkin, we conclude the district court’s findings of drug type and quantity are not clearly erroneous. *15 See Sarabia-Martinez, 276 F.3d at 450; United States v. Maxwell, 25 F.3d 1389, 1397 (8th Cir.), cert. denied, 513 U.S. 1031, 115 S.Ct. 610, 130 L.Ed.2d 519 (1994). Accordingly, we affirm.