Voltage stabiliser. save a bit around 1-2% on my car. in addition u get cooler air con and smoother ride.
Have been using one fuel saving device as they claimed, plugged into the cigarette hole. doesn't work so far
Saw them having booth at JPJ offices in Ipoh. Not sure who allow them to sell there. RM100.
I was like, if that works, something is wrong with the world lol

