Appellant, 19 years old and having pleaded guilty to robbing a McDonald’s restaurant at gunpoint, argues on appeal that the trial court improperly sentenced him to imprisonment as an adult rather than for treatment and supervision under the Federal Youth Corrections Act, 18 U. S.C. § 5005 et seq. (1969).

The sentencing judge had before him at the time of sentencing a recommendation from the Classification Committee at the Youth Center against application of the Youth Act to appellant.1 The court expressly found appellant would not derive benefit from the Youth Act treatment not only, upon the basis of the Committee’s report but also upon its consideration of appellant’s lengthy record of arrests on serious criminal charges and appellant’s failure to refrain from crime even after having been treated as a juvenile.2 Since we do not sit to “second-guess” trial judges or substitute our judgment for theirs in the delicate task of sentencing and since the record reflects (1) a consideration by the sentencing judge of Youth Act treatment before imposing an adult sentence upon appellant and (2) an explicit and reasoned determination by the sentencing judge that appellant would not benefit from Youth *135Act treatment, Lawrence v. United States, D.C.App., 318 A.2d 890 (1974); Reed v. United States, D.C.App., 312 A.2d 775 (1973); Small v. United States, D.C.App., 304 A.2d 641 (1973), the judgment must be and is

Affirmed.