Central spread trough the use of the double diffuser shape design of special double-layer structure, engineer by letting the tail end upwards, spread in Central Groove added a v-shape at the top of the channel. Design of the double diffuser, will be part of idle air flow within the space used up. It through the small hole with the chassis, rising to close to the top of the diffuser air flow loss along the waist, namely trade have said Coke bottle into the central channel of the diffuser, air flow underneath and after the gathering, joint at the rear to create a depression. Efficiency of diffuser to be strengthened.