Description
Product Overview
The Sylvania 921ST Mini Brake Light Bulb is engineered for precise center‑position brake applications. Featuring a machined exterior housing and a specially formulated filament, this 12‑volt bulb emits a bright white light that closely matches OEM specifications. Weighing only 0.16 ounces and measuring 3 x 1 x 4 inches, it offers a compact profile while maintaining robust durability for demanding automotive environments.
Usage
Designed for everyday drivers, fleet operators, and automotive enthusiasts, this bulb excels in city traffic, highway cruising, and adverse weather conditions. Its vehicle‑specific fit ensures seamless installation on a wide range of makes and models, providing reliable braking illumination for passenger cars, light trucks, and SUVs. 
Why Choose Us
Sylvania brings over a century of lighting expertise, delivering OEM‑grade quality to the aftermarket. Each 921ST bulb undergoes rigorous testing for brightness, heat resistance, and lifespan, guaranteeing consistent performance. Our commitment to low maintenance and high durability means fewer replacements and enhanced safety for you and your passengers.
Key Features
- Bright white 12‑volt output for superior brake visibility
- Machined exterior housing resists corrosion and impact
- Vehicle‑specific fit eliminates guesswork during installation
- Long‑lasting filament technology reduces replacement frequency
- Backed by Sylvania’s 100‑year legacy of automotive lighting excellence
FAQ
Can I replace only one bulb or should I replace both?
For optimal performance and consistent lighting, it is recommended to replace both brake light bulbs at the same time.
Is this bulb compatible with LED brake light systems?
The 921ST is a halogen bulb designed for standard brake light circuits; it is not intended for direct replacement of LED modules.
What is the expected lifespan of the 921ST bulb?
Under normal driving conditions, the bulb typically lasts between 1,500 and 2,000 hours, depending on usage and environmental factors.
Do I need any special tools to install the bulb?
Installation requires only basic hand tools such as a screwdriver or trim removal tool to access the brake light housing.
Will this bulb affect my vehicle’s warranty?
Replacing a standard OEM‑specified bulb with an equivalent Sylvania part does not void the vehicle’s warranty, provided the installation follows manufacturer guidelines.








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