When put on the brakes, these 7443 led strobe brake light bulbs will fast flash 3 times on-and-off and then keep solid red light (Legal blinking times) to avoid the rear-end collision for automotive cars, trucks, SUVs, etc. | Can be used for brake lights, tail lights, stop lights, third brake light(center high-mount stop light), etc. Some sensitive vehicles will meet canbus issue after installing, load resistors or flasher relay will be required to solve these issues, you can contact us through Amazon Buyer Message to get help and solutions | Low power and high brightness. 5.5W per 7443 led red bulb. Only 1/4 energy consumption of original 7443 red bulb but 4 times brighter. Built in smart IC driver ensure constant current, no radio interference. Plus instant-on capability with zero warm-up time | Small size comparable to OEM 7440 bulbs Non-polarity, applied to US standard and CK sockets. Fits: 7440, 7441, 7443, 7443LL, W21/5W, 7443/26201, 78660, 78661, 17919, 7515, HIB7443WM, W21W, 7440/26200, 17632, 7504, 7440LL, etc. Amazon filter system may not be 100% accurate or up to date, if you are not sure which bulb model fit your vehicle, please check your vehicle owner manual to confirm or ask a question for help | Unique imitated halogen shape design. Resembling halogen bulb shape design and sequencing 54 pieces 4014-SMD LED chips precisely around the light. Delivering 360° high luminous efficiency with full amber light, easier to be noticed and safer to drive