18W T8 4ft LED Glass Tube - 4000K Cool White

The Knightsbridge T8 4ft LED tube is an 18W direct replacement for traditional fluorescent T8 tubes, delivering 2295 lumens of cool white 4000K light from a 1212mm glass and polycarbonate construction. The tube houses an integral driver and connects to standard T8 lamp holders on 230V mains, providing instant-start operation without the warm-up delay or flicker associated with fluorescent technology.

Designed for commercial and industrial environments including offices, retail units, warehouses and workshops, the tube produces a wide 270-degree beam angle that distributes light evenly across ceilings and work surfaces. The 4000K colour temperature delivers neutral white light that renders colours accurately under a CRI >80 rating, making it suitable for tasks requiring colour differentiation such as print matching, stock checking and assembly work.

The opal diffuser softens the LED point sources into an even glow along the tube's length, reducing glare on computer screens and polished surfaces. At 131 lumens per watt, the tube converts significantly more energy into visible light than equivalent fluorescent tubes, reducing running costs in installations with multiple fittings running extended hours. The rated L70B50 lifespan of 20,000 hours translates to approximately 8-10 years of typical commercial use before light output drops to 70% of original brightness.

The non-dimmable design simplifies installation in switch-only circuits and avoids compatibility issues with dimmer modules. The tube's 27mm diameter matches standard T8 form factor, allowing retrofit into existing fluorescent batten fittings after removal of the starter and ballast components.

Product Specification Sheet

Product Manual

Can this tube replace existing fluorescent T8 tubes?

Yes, but the existing fluorescent ballast and starter must be bypassed or removed first. The LED tube requires direct connection to 230V mains. Many users replace the entire batten fitting with an LED-ready version to simplify installation and avoid rewiring complications.

What colour temperature is 4000K?

4000K is cool white, sitting between neutral and slightly blue-white on the colour temperature scale. It produces brighter, crisper light than warm white (2700-3000K) and is commonly used in offices, retail and commercial spaces where visual clarity matters.

Is this tube dimmable?

No. The integral driver is non-dimmable and must be used on switch-only circuits. Attempting to dim the tube may cause flicker, reduced lifespan or driver failure.

How long does this tube last?

The rated L70B50 lifespan is 20,000 hours, meaning the tube will maintain at least 70% of its original brightness for 20,000 hours of operation. In a typical office running 8-10 hours per day, this equates to approximately 8-10 years before noticeable dimming occurs.