Pet Care, Toys, Supplies and Products for Animals Design JK9 Sync Smart Dog Harness by Alberto Vasquez JK9 Sync is designed to make city living with dogs safer and more comfortable. Thanks to its high-tech knitting material the extremely breathable harness provides an ultra-ergonomic fit while also has extreme tensile strength for control. Its integrated hardware provides high accuracy geolocation to help you find your dog if it gets lost. The hidden LED lights automatically switch on when it's getting dark creating a safe visibility in the city. Built-in movement sensors track your dog's activity level and signals when it drops below healthy.