Product Overview
The original Glass is Class Duo lights were handmade and only rated as weather‑resistant; they relied on 15‑watt bulbs and were limited to 12‑volt systems. Competing dual‑colour lights often use plastic lenses, modest diode arrays and low‑power circuitry. For example, Trux’s dual‑revolution red/white watermelon lights use a clear polycarbonate lens with 19 diodes, operate only at 12 volts and include bullet plugs and a chrome ABS bezel. RoadWorks’ low‑profile red/white light is surface‑mounted with a chrome bezel, uses a clear lens with red primary and white auxiliary modes, and requires a 3‑wire hook‑up with bullet plugs. United Pacific’s “Double Fury” kit also relies on a polycarbonate lens and 19 LEDs, is sealed for 12‑volt systems, and comes with four‑wire bullet leads. These units often produce a generic glow rather than a defined beam, and their plastic construction can yellow or crack over time.
The Gen 2 Duo addresses these shortcomings. Each light pairs our signature tempered red glass star lens with the machine‑built AlphaFit Duo bulb. This 23‑watt LED uses two banks of chips per side—one for red and one for white—to produce a sharp, travelling starburst beam. Unlike earlier models, the bulb is manufactured with tight tolerances and undergoes rigorous quality control to ensure reliability and uniform colour. The aluminium body is anodized and oversized for superior heat dissipation; combined with a passive radiator and hidden high‑speed fan, it keeps the LEDs cool for continuous operation. A thick silicone gasket seals the lens to the housing and creates an IP68 waterproof assembly similar to our single‑colour Gen 2 lights. Positive‑pressure venting and one‑way check valves purge moisture while blocking contaminants, eliminating the fogging problems seen on earlier duo lights and rival products.
Key Features & Benefits
Real Tempered Red Glass Lens with White Override
Our vintage‑style red glass lens produces a deep starburst beam that radiates in all directions. The glass is optically clear, scratch‑resistant and won’t yellow like polycarbonate competitors. Behind it, the white secondary bank creates a crisp cool‑white beam for utility lighting. Because the secondary colour overrides the primary when both wires are powered, you can switch from red to white instantly without complicated relays—perfect for work lights, show modes or interior lighting.
AlphaFit Duo 23‑Watt 3‑Wire LED Bulb
The heart of this light is our AlphaFit Duo bulb. Built with the same low‑surface‑area LED architecture as our single‑colour Gen 2 bulbs, it uses two separate chip banks to achieve dual colours. At 23 watts, it eclipses the 15‑watt output of the original duo lights and delivers far more intensity than typical 19‑diode dual‑revolution lights rated around 240 mA per colour. The 3‑wire harness includes a ground lead, a red‑trigger lead and a white‑trigger lead; applying power to both triggers automatically selects white. No external modules are needed, and wiring is straightforward for marker lights, toggle switches or auxiliary circuits.
Dual‑Voltage Compatibility
Unlike many dual‑colour lights that operate only on 12 volts, the Gen 2 Duo accepts 12‑ or 24‑volt inputs without additional resistors or transformers. It fits any H11‑style socket and mounts in standard 3‑inch glass watermelon housings, making it ideal for semi‑trucks, classic rigs, farm equipment and custom cars.
Machine‑Built, Waterproof and Ventilated
Each AlphaFit Duo bulb is machine manufactured with tight tolerances and strict QC—unlike the hand‑assembled first generation, which was merely weather‑resistant and prone to failure. The oversized aluminium heat sink, passive radiator and hidden high‑speed fan pull heat away from the LEDs, while a thick silicone gasket and anodized aluminium housing create a robust seal. Positive‑pressure venting with one‑way valves purges condensation but blocks external moisture, achieving an IP68 waterproof rating similar to our single‑colour Gen 2 lamps. Competing dual‑colour lights often lack this technology; Trux’s units are only IP67 and rely on sealed plastic housings, and RoadWorks’ low‑profile lights use rubber gaskets but do not vent moisture.
Versatile Wiring & Override Control
The Gen 2 Duo’s 3‑wire design gives you full control over colour. You can wire the red lead to your marker lights and the white lead to a switch, tie both into a 3‑way toggle, or integrate them into auxiliary circuits. If both leads are powered, the white mode overrides red automatically—an override feature absent on some older dual‑colour lights that require complex switches. This simple logic makes our lights ideal for interior bunk lamps, work lights, courtesy lights or show‑rig accent lighting.
1‑Year Warranty & Support
We stand behind every Gen 2 Duo with a 1‑year warranty. The first‑generation duo lights carried only a six‑month warranty, and competitor dual‑colour bulbs like Grand General’s 1157 switchback LEDs are limited to six months. Our improved manufacturing and sealed design ensure long‑term reliability, and our North American support team is ready to help with fitment or wiring questions.
Performance / Compatibility / Use-Case
The Glass is Class Duo Gen 2 Red/White operates on 12 V or 24 V systems and draws approximately 23 watts per bulb. It produces a brilliant red beam for running or marker applications and an even brighter white beam for work lights or interior lighting. The small surface emission area eliminates the dark void found in many multi‑diode lights, producing a uniform starburst pattern. Because of its intensity, this light is intended for off‑road and show use only; it is not SAE/DOT compliant—similar to the previous generation—and should not be used as a primary stop/turn/tail lamp on public roads.
Whether you’re outfitting a semi‑truck, tractor, classic pickup or custom build, the Gen 2 Duo’s versatility makes it ideal for marker lights, bunk lamps, cargo lamps or under‑cab accents. Its dual‑voltage capability also suits RVs, heavy‑duty equipment and marine applications.
Installation / Fitment / Technical Details
The Gen 2 Duo Red/White light installs in any standard 3‑inch glass watermelon housing. Simply remove your existing bulb, insert the AlphaFit Duo into the H11 socket and secure the glass lens with the provided silicone gasket. Connect the ground wire to chassis ground, the red trigger wire to your marker/running lamp circuit and the white trigger wire to a switch or auxiliary circuit. When both red and white triggers are powered, the bulb will select white automatically.
Because the LED module is sealed and ventilated, it can be mounted horizontally, vertically or inverted without compromising performance. Mounting brackets are sold separately; choose a mirror mount, under‑glow bracket or flush‑mount kit to suit your application.
Build Quality / Warranty
Our tempered red glass lens is thick and abrasion‑resistant. The AlphaFit Duo bulb features an anodized aluminium body, an aluminium radiator fin array and a quiet, long‑life cooling fan. Positive‑pressure venting prevents moisture buildup while allowing heat to escape. An oversized silicone gasket ensures an IP68 seal at the lens interface.
Every light is assembled under ISO‑certified quality systems and undergoes final testing for colour accuracy, current draw and water ingress. We back each unit with a 1‑year warranty, surpassing the 6‑month warranty on earlier models and longer than the 6‑month coverage for many 1157 dual‑colour replacement bulbs.
Warranty: 1-Year Limited Warranty
Designed and validated by Alpha Series Lighting for real-world truck environments.
⚠️ Not SAE/DOT compliant
These lights are intended for show, off-road, and auxiliary use only due to extreme brightness.
What’s Included
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1 × Glass is Class Duo Gen 2 Red/White Watermelon Light (tempered glass lens and housing)
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1 × AlphaFit Duo 23‑Watt Red/White LED Bulb
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Pre‑installed silicone gasket and vented housing
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Installation guide (digital download)
Frequently Asked Questions
What makes the Gen 2 Duo different from the previous generation?
The Gen 2 Duo uses a 23‑watt machine‑built LED bulb with two chip banks (red and white). It is sealed to an IP68 rating and includes an active cooling fan and anodized heat sink. The original Glass is Class Duo operated at 15 watts, was hand‑assembled and only weather‑resistant, which led to higher failure rates and moisture issues. The new version also supports 12‑ or 24‑volt systems and comes with a 1‑year warranty.
How does the 3‑wire override function work?
Each AlphaFit Duo bulb has a ground wire, a red trigger wire and a white trigger wire. When you power the red wire, the bulb emits red light. When you power the white wire, it emits white light. If you power both wires simultaneously, the white chip bank overrides the red and the light outputs white. This logic lets you use a simple toggle switch or tie the red wire to your marker circuit and the white wire to a separate accessory switch. Competing dual‑colour lights may not include this override and instead require a 3‑way switch or multi‑wire module.
Are these lights legal for road use?
No. Like the first‑generation duo, these lights are intended for show rigs, off‑road vehicles and interior applications only and are not SAE/DOT compliant. They are extremely bright and may be considered distracting on public roads. Use them responsibly and check local regulations before installation.
Will this light fit my truck’s electrical system?
Yes. The Gen 2 Duo Red/White operates on both 12‑volt and 24‑volt systems, making it compatible with most heavy‑duty trucks, pickups and off‑road equipment. Simply connect the 3‑wire harness to your existing wiring as described in the installation section. Competitor dual‑colour lights such as Trux’s dual‑revolution units are limited to 12 volts, so they may not function properly on 24‑volt systems without additional modules.
How does this compare to dual‑colour LED replacement bulbs?
Dual‑colour 1157 switchback bulbs like those sold by Grand General use 15 surface‑mount LEDs and operate only at 12 volts. They require an 1157 socket, have no active cooling and often include only a six‑month warranty. The AlphaFit Duo is a purpose‑built LED module with an H11 base, active cooling, a 23‑watt rating and a 1‑year warranty. It also features a sealed and vented design with IP68 protection, making it better suited for high‑intensity show lighting and prolonged use.
