The 1157 is a dual filament bulb while the 1156 is a single filament bulb. They look very similar but are not interchangeable. A common mistake is to put an 1156 into a socket for an 1157 bulb. This causes all kinds of weird problems like dash lights going on when you step on the brake. You can see in the pictures below that the 1157 has two brass terminals in the base while the 1156 has only one. The 1157 bulb is also keyed so it will only go into the socket one way. Note that one lock tab on the 1157 is higher than the other. This prevents it from going in wrong. Also note that the lock tabs on the 1156 are the same height so it will not go into an 1157 socket.
Sylvania SilverStar High Performance Signal Lighting double filament bayonet base (27 watts). Gives you crisp, clean styling of clear lens signal designs and produces 100% street legal amber light when lit. SilverStar Signal Lighting features the latest breakthrough in European Diadem interference coating technology to produce a signal lamp that is iridescent blue when unlit and legal amber when lit. Use wherever it calls for an 1157 amber bulb. Includes two bulbs. Not sure what your vehicle)'s bulb style
GMC Safari signal light rear turn signal blinker light bulb 95 Super Bright RED 1157 LED light bulbs OEM light Bulb with Build in 12 super LED. Twist in bulb-Double filament. Manufactory part no: 1157, 3496, 2057, 1142, 12499, 12594, P21/5W -- Newest bulb upgrades for your car, truck or SUV - Super High Intensity 1157 Super Ultra Bright LED, automotive LED Light, car replacement bulb. (Multi-LED wide light source-designed automotive LED replacement light bulb for car.)With all the new technology coming out
Incorporates dual circuit operation, meaning the central array is lit at full brightness all the time for normal running lamp operation The outer L.E.D. array lights up to full brightness when brake or turn signal is applied... this not only results in brighter running lamp mode but a much more dramatic, highly visible, differential between running and brake lamp modes Chrome-plated built-in 45 degree reflector mirror for both side and rear light disbursement 1157 Bulb is made to be used as a taillight for
