GU10 LED Bulb 5W Cool White 4000K Dimmable 74mm

This bulb has a 74mm barrel versus the standard 58mm. It is designed for deep recessed downlight fittings where a standard bulb sits too far back inside the housing, causing uneven light distribution or a visible dark ring. If your downlight has a deep housing, this extended barrel ensures the bulb sits at the correct depth. Measure your housing depth before ordering to confirm compatibility.

Yes — this bulb is dimmable. Use a trailing edge (LED-compatible) dimmer switch for best results. Standard leading edge dimmers may cause flickering or buzzing. Trailing edge dimmers are usually labelled TE or LED on the switch plate. If you are not using a dimmer switch at all, a non-dimmable GU10 alternative may perform more consistently — contact us for advice.

Designed for GU10 (push-and-twist) deep recessed downlight fittings. Before ordering, confirm both the cap type (GU10) and the housing depth (minimum 74mm clearance). This bulb produces 4000K cool white — a clear, neutral tone suited to kitchens, bathrooms, and task areas. Browse our LED bulbs collection for other colour temperatures and barrel lengths.

4000K cool white will feel clinical in a living room or bedroom — it is not the right choice for atmospheric or relaxation lighting. For those spaces, 2700K extra warm white or 3000K warm white is more appropriate. 4000K is best suited to kitchens, bathrooms, home offices, and task areas where visual clarity matters more than ambience.

This bulb delivers 460lm versus the 500–600lm typical of a standard 5W GU10. The extended 74mm barrel geometry affects the optical path, which results in slightly lower measured lumen output. In practice, the difference is not perceptible in normal use — the extended barrel ensures the bulb sits at the correct depth in a deep housing, which produces better light distribution than a standard bulb sitting too far back.