Description
This Universal Parts tail and brake light bulb restores running-light and brake-light illumination in one straightforward replacement. Its dual-filament 12V 21/5W design fits matching BAY15d sockets on scooters and other powersports equipment, including CSC go. scooters and compatible 139QMB and GY6 models.
Features
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Two lighting functions: A 5W filament provides the running light, while the 21W filament provides the brake light.
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Universal socket-based fit: Suitable for scooters and other powersports equipment requiring a 12V 21/5W BAY15D bulb.
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Dual-filament incandescent design: Clear glass bulb with separate tail- and brake-light filaments.
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BAY15d bayonet base: Double-contact base with offset-height retaining pins for a matching socket.
Specifications
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Brand: Universal Parts
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Part number: 0900-4021
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Alternate references: 138-37-10PCS, 138-37-1PC
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Voltage: 12V
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Brake-light filament: 21W
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Running-light filament: 5W
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Base: BAY15d (1157-style), double-contact bayonet
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Base diameter: 15 mm
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Retaining pins: Offset in height, one higher than the other
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Base contacts: 2
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Light source: Dual-filament incandescent
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Glass: Clear
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Quantity: 1 bulb
Model Fitment
Universal replacement for scooters and other powersports equipment using a BAY15d socket and requiring a 12V 21/5W dual-filament tail/brake bulb. Commonly found on 139QMB and GY6 model scooters; fitment is determined by the bulb socket, voltage, wattage, and housing clearance, not the engine alone.
| Application |
Fitment |
| Chicago Scooter Company |
CSC go. scooters |
| 139QMB-based 50/80cc scooters |
Matching BAY15d tail/brake sockets; includes 139QMA, 139QMB, 1P39QMB, 1P39QMA-2, YN139QMB, JJ1P39QMB, 139FMA-2, BD1P39QMB, BN139QMB, 147QMD, and other QMA/QMB applications when the bulb specifications match |
| GY6 scooters |
Models requiring a 12V 21/5W BAY15d tail/brake bulb |
| Other powersports equipment |
Any make or model with a matching BAY15d socket, 12V 21/5W requirement, and adequate bulb clearance |
How to identify the base: The BAY15d (1157-style) base is 15 mm in diameter, has two electrical contacts on the bottom, and uses two retaining pins at different heights. Compare these details with your original bulb and socket, then confirm the 12V 21/5W requirement and bulb clearance. BAY15d and BA15d are different base specifications; this bulb requires a BAY15d socket.
Product Diagrams
