it is a device which is change the original ignition point,calculated for a correct gasoline running of the carit is a device which is change the original ignition point,calculated for a correct gasoline running of the car,to adapt it to alternative fuels like LPG and CNG.these have a slower combustion time in comparision to gasoline,therefore it is necessary for the spark to ignite in advance in comparision to the original point. 

CNG ignition advancer Timing Advance Processor