Systema Professional Training Weapons (PTW) are the most premium electric Airsoft guns today. Using computerized optical technology, PTWs offer precise trigger control that simulates the feeling of a real gun. Simply tap the trigger once and the computer will do the rest to complete the firing cycle. Semi-only and 3-Burst modes are also available on select models. Interchangeable power cylinders (sold separately) allow you to change the power output in less than 10 seconds with no tools. Real steel dimensions means that the PTW can fit all accessories designed for real guns, giving you endless customization options. And realistic bolt lock function disengages the trigger once the magazine is empty; perfect for real world training.