United States Court of Appeals
                            FOR THE EIGHTH CIRCUIT
                                   ___________

                                   No. 07-2283
                                   ___________

United States of America,               *
                                        *
             Appellee,                  *
                                        * Appeal from the United States
     v.                                 * District Court for the
                                        * Northern District of Iowa.
Hector Lopez, also known as D,          *
also known as Felix Lopez, also         *
known as Diablo,                        *
                                        *
             Appellant.                 *
                                   ___________

                             Submitted: March 11, 2008
                                Filed: May 20, 2008
                                 ___________

Before RILEY, GRUENDER, and SHEPHERD, Circuit Judges.
                            ___________

RILEY, Circuit Judge.

       Hector Lopez (Lopez) pled guilty to one count of conspiracy to distribute five
hundred grams or more of a mixture or substance containing a detectable amount of
methamphetamine, in violation of 21 U.S.C. §§ 841(a)(1), 841(b)(1)(A) and 846.
Before sentencing, Lopez and the government negotiated an agreement resulting in
a stipulation signed by both parties. Lopez signed a stipulation stating, “defendant
agrees that a sentence within the guidelines range of 360 months to life is reasonable
and agrees not to seek a sentence outside of this guideline range.” This stipulation
was the product of negotiations between Lopez and the government in which “Lopez
agrees to withdraw his objections to the final presentence investigation report, with
the exception of paragraph 40, which states that the defendant used or attempted to use
a person less than 18 years of age in his offense. The government agrees not to pursue
this two-level adjustment to the defendant’s guideline range.” Lopez also agreed “to
withdraw any motion for variance or departure.” The district court1 sentenced Lopez
to 600 months imprisonment. On appeal, Lopez contends the 600-month sentence
was unreasonable when measured against the requirements of 18 U.S.C. § 3553(a).

        “[A] defendant who explicitly and voluntarily exposes himself to a specific
sentence may not challenge that punishment on appeal.” United States v. Cook, 

, 1128 (8th Cir. 2006). Lopez signed a stipulation stating, “a sentence
within the guidelines range of 360 months to life is reasonable.” This stipulation was
the product of counseled negotiations between Lopez and the government. Lopez
explicitly and voluntarily exposed himself to a sentence in the range of 360 months
to life and acknowledged any sentence in this range was reasonable. This stipulation
was supported by consideration, given the government’s agreement not to pursue the
two-level adjustment for using a person under eighteen years of age. See United
States v. Sanchez, 

, 460 (8th Cir. 2008) (“Plea agreements are contractual
in nature and should be interpreted according to general contract principles.” (citation
omitted)). Lopez does not raise any legal or equitable challenges to his negotiated
stipulation. Consequently, Lopez may not now contest his 600-month sentence on
appeal, a sentence falling within the agreed sentencing range. For the reasons stated,
and finding no manifest injustice, we affirm.
                        ______________________________




      1
        The Honorable Mark W. Bennett, United States District Judge for the Northern
District of Iowa.

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