VASER is a fat pretreatment device based on the emission of pulsed or continuous ultrasound energy to emulsify fat before its aspiration by means of suction-assisted lipoplasty or power-assisted lipoplasty. If compared with previous generation UAL machines, it carries important technologic advances that focus on the safety and efficiency of the process. VASER is the result of improvements in surgical instrumentation and technique, proper use of wetting solutions, and knowledge about the best use of ultrasound for fat fragmentation. With its thinner cannulas and decreased use of ultrasonic energy, it allows greater emulsification of fat, creates more tunnels, diminishes the operative time, preserves vessels and nerves, and causes less pain and hematomas.