Well, you just buy the regular glass plate cover and have it tinted at your suking car tint store. In fact, if you are really a suki in a car accessory store, they might tint it for you for free. Anyway, I suggest either a minimum of medium-black or light-silver 3M or magic tints. Just make sure the tint is dry before installing. (Note: silver tints over your license plates makes them harder to read at a distance because they reflect local scenery.)
Typical medium tinted plates can be read from a distance of approximately five meters or closer. Of course, since your car is moving (fast)...
Disabling the license plate lights (by removing the bulbs or connectors) also helps at night.