P21W, PY21W, P21/5W
|How do I choose the right LED Bulb size for my car?

 P21W, PY21W, P21/5W, are all commonly used car light bulb base, do you often confuse these? This article will help you to solve the confusion, so that you won’t buy the wrong specification, only to find that you can’t use it at home!

So you definitely need to know this :

1. How to recognize Various Names?


According to different countries can also be called: BA15S, S25, 1156



Depending on the country, it can also be called: BAU15S, 1156



Depending on the country, it can also be called: BAY15D, 1157


Generally there will be different names for different wattages.

Because directional light bulbs often use 21W power, they are also called P21W, PY21W, P21/5W.

2. How to recognize the difference?

You can compare the difference from the appearance



The two bumps are 180 degrees apart, with a pin angle at the bottom.



Two bumps 150 degrees apart, one connected pin angle at the bottom.



Bumps are usually high and low, with two connected pin angles at the bottom.

What is P21W, PY21W, P21/5W used as?

a. Turn signal

b. Brake light

c. Daytime Running Lights



Q1. How do I know the specification of my car?

You can check your car’s manual, take out the light bulbs from your car, or ask the seller directly.


Q2.What should I do if I bought the wrong base?

If you are a perfectionist, we suggest you return it for the correct base.

If you don’t care much about it, you can grind off one of the bumps, it won’t affect the use.

15 years of LED brand in Taiwan

Leave Your Comment!

About Per-Accurate

We are a company providing LED light products for vehicles, e.g., headlights, light bulbs, turn lights and worklights. We have built a global supply chain from LED manufacturers to terminal clients. Besides, we also furnish LED products of the best quality with customers via Amazon, Ebay, Alibaba Express, Wish and our official shopping platform.

Latest Articles

Follow US

Subscribe Us

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Ut elit tellus, luctus nec ullamcorper mattis, pulvinar dapibus leo.