Product Specifications

Overview:
The S3 P26s is a low-wattage halogen bulb primarily used as a side marker light, clearance light, or position light on motorcycles, mopeds, and some small special vehicles (such as ATVs and agricultural machinery). Also known as a "side light," its core function is to mark the vehicle's width and outline at night, not to provide road illumination.

Core Features and Specifications:

1. Model & Specifications

   • S3: This is its optical and electrical designation. The S3 refers to a single-filament, low-wattage miniature bulb, typically used for auxiliary signaling or marking.

   • Rated Voltage & Wattage:

     • Operating Voltage: 12V.

     • Standard Wattage: Typically 4.2W or 4W. This is a very low power consumption designed for prolonged use without burdening the vehicle's electrical system.

   • P26s: This is its base/bayonet type. It is a single-contact, prefocused bayonet base with offset (asymmetrical) double locating pins.

     • “P” stands for Prefocused, meaning the filament position is fixed precisely relative to the base to ensure the light beam is directed as designed.

     • “26” is the model code.

     • “s” typically denotes Single Contact, and its two locating pins are offset (one high, one low or asymmetrical). This ensures the bulb can only be inserted into the socket in one correct orientation, guaranteeing proper light projection.

2. Working Principle & Application

   • Working Principle: As a simple single-filament, single-contact bulb, it lights up when powered.

   • Primary Applications:

     • Motorcycle/Moped Side Marker/Clearance Lights: Installed on the front sides (and sometimes rear) of the vehicle to indicate its width.

     • Position Lights: Serves as supplementary front/rear position lights on vehicles without dedicated "parking light" designs.

     • Instrument Panel Backlighting: In rare cases on older models, it may be used for instrument illumination.

     • Warning Lights for Special Machinery: Used for warning or position marking on low-speed vehicles like ATVs and forklifts.

3. Key Distinctions & Compatibility

   • Vs. Headlight Bulbs (e.g., H-series): The S3 has an extremely low wattage  and is used only to emit signal light, not to illuminate the road. Its luminous flux is much lower than any headlight bulb.

   • Vs. Other S-Series Signal Bulbs (e.g., S2, S8): The S3 is a low-power, single-function light. The S2 is a single-filament, dual-power tail/brake light. The S8 often refers to higher-power single-filament bulbs (e.g., P21W).

   • Base Compatibility: Bulbs with a P26s base are not interchangeable with those using P26d or other similar-sized bases with different pin layouts. Its offset pin design is a fool-proof feature that enforces correct installation.