Review on 🚦 Alla Lighting 3156 3157 LED Bulbs 3000lm - Ultra Bright Amber Yellow Turn Signal Lights for Cars Trucks T25 3057 3457 4157 4057 by Vincent Burton

Take a close look at the plastic knife that fits into the car's socket. Look at the side of the blade and notice the small ridge sticking out. This is the "key" that will (theoretically) allow you to install the bulb only one way and not the other way around. In this case, note that the protrusion of the small key is about 1/3 of the width of the blade. That's right, that's the way it's supposed to be, and that's what a standard factory bulb looks like. However, these lamps have a tongue that is 2/3 the width of the blade, which prevents the lamp from being inserted. So. Be careful, you may find that these bulbs are either poorly made, falsely advertised as a weird key, or just really poorly made. Definitely check this when purchasing and make sure the key is the correct shape before attempting to install the bulb.