Delayed gratification typically doesn’t rate highly among teenagers, a phenomenon that members of the Chester County K-9 Unit understand all too well.“I know you’re not excited about listening to me,” acknowledged Deputy Mike Sarro during a recent visit to Downingtown East High School. “But you will get to meet my partner.”Sarro explained that he needed to provide a brief overview of the program before introducing one of the event’s stars: a high-energy Belgian Malinois named Dexter. Sarro knew from experience that once Dexter arrived, the dog would hog the spotlight.Minutes later, students in Mary Beth Scott’s Business & Personal Law class oohed and awed as Dexter made his entrance, reinforcing his reputation as an accomplished educational tool for students. Sarro took his K-9 partner through a series of tasks to demonstrate his obedience as well as his expertise in sniffing out illicit drugs.The exercise prompted a gentle warning from Sarro. “Don’t even think about ever having them [drugs] because the dog will find them,” he said.The students learned that the dogs live with their handler and that they adopt a different persona when they stop working and fulfill the role of family pet. Ongoing training accounts for the dogs’ enviable behavior, Sarro stressed. The dogs and trainer initially earn certification after a challenging 400-hour regimen. After that, each team does at least 16 hours of training per month.Recalling some of the details that he and Dexter have shared, Sarro said one particularly satisfying outing culminated with finding a disoriented person who had gotten lost in the woods. Other rewarding encounters involved fugitives who surrendered as soon as the K-9 team arrived. “They didn’t want to get bitten,” Sarro said, adding that the alleged crooks knew they couldn’t outrun the dog.Such instances underscore the vital importance of good training, he said. “If someone you’re seeking suddenly decides to come out with his hands up, you have to be able to call off the dog,” Sarro explained.After fielding questions from the students, Sarro turned the program over to Deputy Matthew Mendenhall, who provided the class with another treat: interaction with Nero, a regal German shepherd who specializes in explosives detection, followed by another Q&A.Mendenhall, who joined the Chester County Sheriff’s Office a year ago, explained that although he had years of experience as a K-9 supervisor in the Berks County Sheriff’s Office, he had never been a handler until late last year.“This has been a great experience; I’m really enjoying it,” Mendenhall said, urging the students to pursue their passions.Such presentations have become routine for members of the Chester County Sheriff’s Office K-9 Unit. Lt. Harry McKinney, who heads the 10-team unit, said its members regularly provide crowd-pleasing demonstrations at a host of venues, ranging from community events to school appearances.Deputy Ryan Barr, who has participated in dozens of school outings with his K-9 partner, a bomb-sniffing German shepherd named Murphy, said he particularly enjoys the special identification he has with the young people.“I can remember sitting exactly where they are,” he said. “My first experience with a K-9 officer was at Parkside Elementary School in Delaware County.”Barr said he was in second grade when Brookhaven Police Chief John Eller and Parkside Police Chief John Flynn gave a presentation. “I knew from 2nd grade on that I would have a career in law enforcement,” Barr said. “I owe my success in law enforcement to men like Chief Flynn, Chief Eller, and many other officers who shaped my youth through school demos and community policing. My hope is to inspire a new generation of future law enforcement officers to rise to the occasion.”Besides drug and explosives detection, the Chester County K-9 Unit features dogs with expertise that include searching for accelerants in suspected arson cases, defusing stressful situations, providing comfort to crime victims, and locating human remains. In addition to their individual specialties, the dogs are all trained in tracking.McKinney said the K-9 teams, which each average about a 100 calls a year for service, are on call 24 hours a day. Because no one can predict when a team might be needed to clear a building after a bomb threat or apprehend a fugitive, those who request a K-9 visit are always advised that it could be postponed on short notice.Fortunately, none of the scheduled appearances to date has been preempted by a call for service, but the risk exists. “On a daily schedule, we never know when a request for tracking, searching, or securing a building after a bomb threat will occur,” McKinney said. “Unfortunately, the demand for service sometimes exceeds the supply of dogs.”McKinney recalled one day when the unit received 11 calls and had to enlist backup from other units in the region. He explained that each call has to be independently assessed. “Some calls can be delayed while others require immediate attention,” he said.The unit wishes it could accommodate all of the requests for demonstrations it receives, but there just aren’t enough hours in the day, McKinney said. Larger groups can be handled more efficiently so he often encourages teachers or Scout leaders to see if any of their colleagues want to collaborate.The visits with the public produce a multitude of rewards, according to Chester County Sheriff Carolyn Bunny Welsh.“Not only are the presentations appreciated, but they also provide valuable information about how the K-9 teams work,” she said. “Each of the handlers and their K-9 partners excel in their specialty, and each team provides benefits to law enforcement as well as citizens.”Another bonus: The deputies often get thank-you notes from younger audiences. These treasured keepsakes typically reference the students’ takeaways from the presentation. One second-grader from General Wayne Elementary marveled at the fact that the dogs get rewarded for performing tasks with play time, sagely concluding “there is training in playing.”Welsh started the Chester County Sheriff’s Office K-9 Unit in 2006 with two dogs trained in explosives detection. Since then, she has gradually increased its size and scope. The office currently serves Chester County’s half-million residents in 73 municipalities – 53 of which have their own law-enforcement departments. Besides the Sheriff’s Office, only three other county agencies -- West Chester University, Lincoln University, and North Coventry Township -- currently have a K-9 presence.Welsh credits the program’s successful expansion to the efforts of McKinney, a master trainer for the National Association of Professional Canine Handlers, and Chester County Deputy Sheriff Paul Bryant, a Level III trainer for the U.S. Police Canine Association. In 2016, the pair initiated an in-house training program to strengthen the skills of the existing teams. The program also generates revenue since outside agencies use the services.Anyone interested in scheduling a K-9 visit, which should be done at least 30 days in advance, should contact McKinney at 610-344-4314. Requests should include the date, time, and a cellphone number for the organizer.“We’re extremely proud of the CCSO K-9 Unit and the services it provides,” said Welsh, adding that sharing those experiences enhances them for everyone involved.