While the actual accelerating structure is only 3.3 cm, the laser that drives the acceleration is the size of a two car garage. The huge advantage of LPA is size of the accelerating gradient typically measured in V/m. The LPA could reach 100E9 V/m while the best RF structures will never exceed 100E6 V/m due to material limits. Whether the LPA will be man portable like a power tool or vehicle portable is yet to be determined. It is exciting work doing some really great physics.