380 Bulb 12V 21/5W P21/5W - Brake Tail Light Bulb BAY15d - Classic

Standard dual-filament automotive bulb with bayonet-fit BAY15d base, designed for stop/tail and brake/side light applications. The Classic 380 bulb (also known as P21/5W) operates at 12 volts with 21W for bright brake lights and 5W for rear running lights. E-marked and ECE Regulation 37 approved for road-legal use in UK and European vehicles. Suitable for cars and motorcycles requiring dual-intensity rear lighting.

Key Features

• Dual Filament Design: One bulb handles both parking (5W) and braking (21W) intensities
• BAY15d Bayonet Base: Double contact, offset pins for secure twist-and-lock installation
• High Output: 460 lumens (21W) for brake lights, 40 lumens (5W) for tail lights
• High Vibration Resistance: Designed to withstand automotive and motorcycle vibration
• Road Legal: E-marked and ECE Regulation 37 approved for UK and European compliance
• Original Quality: Reliable halogen technology for consistent dual-intensity performance
• Wide Compatibility: Suitable for many car and motorcycle models with BAY15d sockets

Technical Specifications

Application & Usage Guide

Primary Applications:

• Brake lights / Stop lights (21W filament)
• Tail lights / Rear position lights (5W filament)
• Rear side lights (5W filament)
• Combined brake/tail light clusters

Also Known As: P21/5W, BAY15d bulb, 380 brake/tail bulb

How Dual Filament Works: The 380 bulb contains two separate filaments within one glass envelope. The 5W filament illuminates when your sidelights or headlights are on (providing rear position lighting), while the brighter 21W filament activates when you press the brake pedal. This dual functionality saves space and simplifies vehicle wiring.

Installation: Align the offset pins on the BAY15d base with the socket slots, insert the bulb, and twist clockwise to lock in place. The offset pin design ensures correct orientation. Always ensure the ignition is off before replacing bulbs and replace in pairs for consistent appearance.

Compatibility: Suitable for most cars and motorcycles with 12V DC electrical systems requiring P21/5W bulbs with BAY15d double-contact base. Check your vehicle handbook or existing bulb to confirm 380/P21/5W fitment before purchase.

Important Safety & Compatibility Information

• Always verify bulb type in your vehicle handbook before purchasing
• Switch off ignition and allow bulbs to cool before handling
• Do not touch glass with bare hands; use a clean cloth to avoid oil contamination
• Ensure bulb is correctly seated and twisted to lock in socket
• Replace brake/tail bulbs in pairs for consistent light output and appearance
• Test both filaments after installation (sidelights and brake lights)
• The offset-pin design ensures correct installation orientation
• Dispose of used bulbs responsibly at household waste recycling centres
• Keep out of reach of children

SHIPPING & RETURNS

Shipping:

• Fast UK delivery available
• Local collection option at checkout
• Orders dispatched within 1-2 working days
• Tracked shipping on all orders

Returns:

• 14-day return policy on unopened products
• Items must be unused and in original packaging
• Contact gtmotorspart@outlook.com for return authorization
• Opened bulbs are non-returnable for safety and hygiene reasons

WHY CHOOSE US

• Trusted Quality: Genuine OEM-approved parts and premium fluids from authorized suppliers
• Competitive Pricing: Best value on premium automotive oils and maintenance products
• Fast Local Delivery & Collection: Quick dispatch with flexible delivery and collection options across the UK
• Friendly Support: Expert advice and customer service from automotive specialists