Judgment, Supreme Court, Bronx County (Frank Diaz, J.) rendered February 15, 1991, by which defendant was convicted, after a jury trial, of criminal sale of a controlled substance in the third degree and sentenced as a second felony offender to a term of 10 to 20 years in prison, unanimously modified, as a matter of discretion in the interest of justice, to the extent that defendant’s sentence is reduced to 5 to 10 years in prison, and otherwise affirmed.
Defendant was arrested and convicted for selling twenty dollars worth of cocaine to an undercover police officer. Upon our examination of this record we find that even though the defendant had a prior conviction, the sentence imposed for this single sale was excessive and we reduce the sentence accordingly (People v Acosta, 180 AD2d 505, lv denied 80 NY2d 827; People v Morales, 181 AD2d 572, lv denied 80 NY2d 835). To the extent that the defendant preserved his claim relating to admissibility of background evidence concerning police procedures, we find that the evidence in this case was properly admitted to aid the jury in understanding the officers’ conduct and was probative of their credibility (People v Almodovar, 178 AD2d 133, lv denied 79 NY2d 943). Concur—Sullivan, J. P., Ellerin, Wallach, Kupferman and Ross, JJ.