Although many cars using 4157nak bulbs, I am sure most people don’t know what’s means about 4157nak bulb.

I would like to give you explaination about 4157nak bulb as below.

“Na” means amber color.

“K” means put krypton gas inside 4157nak bulb.

Comparing with standard 4157 or 4157na bulb, 4157nak bulb are longer life time.

In order to make you clearly 4157nak bulb, I will attach picture to your information.

The following picture is 3157nak bulb, which is the same as 4157nak bulb.