GU5.3 LED MR16 Bulb 3.4W 345lm Non-Dimmable - Warm White 3000K

This is a low voltage LED spotlight with the two pin GU5.3 cap, the shape the trade still calls MR16. It draws 3.4W and puts out 345 lumens at 3000K, a warm white close in tone to the halogen reflectors these were made to replace. The beam measures 36 degrees, described on the pack as a narrow cone, so the light lands in a defined pool rather than spilling across the whole ceiling. The energy rating is E, and the pack prints a 15 year lifespan of 15,000 hours.

GU5.3 belongs to low voltage lighting: recessed downlights, display and cabinet fittings, and kitchen ceilings wired through a transformer rather than straight to the mains. It is not interchangeable with GU10, which has two thick pins with heads that twist and lock into the holder. GU5.3 has two thin straight pins that push in, so pull the old lamp out and look at the pins before you order. Over a worktop or along a run of shelving, 3000K keeps wood, brass and cream paint looking warm rather than clinical, and the narrow cone means each lamp marks out its own pool of light.

There is no dimming here: the pack marks it non-dimmable, so put it on a plain switched circuit and choose a dimmable lamp if you want the level to vary. A 3.4W lamp also asks far less of a transformer than the 35W halogen the pack names as its equivalent, and older electronic transformers have a minimum load they need to see, so check yours if you are changing a whole run at once. Each unit is a single bulb in its own box, with a minimum order of 12, sold in multiples of 12. It sits alongside our wider range of LED bulbs in fittings including GU10, B15 and 2G11, in warm white and cool white.

Will this fit a GU10 downlight?

No. GU10 has two thick pins with locking heads that twist into the holder, while GU5.3 pushes in on two thin straight pins. Take the old lamp out and compare the pins before ordering.

Do I need a transformer for this bulb?

GU5.3 fittings are low voltage, so they are fed from a transformer or driver rather than wired straight to the mains. If your holder already takes GU5.3 pins, that supply is in place.

Can I put it on a dimmer?

No. The pack marks it non-dimmable, so it belongs on a plain switched circuit. If you want to vary the level, choose a lamp sold specifically as dimmable instead.

How bright is 3.4W against the halogen it replaces?

It gives 345 lumens, and the pack names it as a 35W replacement, so a run of these draws a small fraction of the old load for a comparable level of light.

What does warm white at 3000K look like in a room?

Softly yellow rather than blue, a shade crisper than an old filament bulb but still kind to wood, brass and cream paintwork. It suits kitchens, living rooms and display shelving.

How wide is the beam?

Thirty six degrees, which the pack calls a narrow cone. Expect a defined pool of light under each lamp, better for worktops, pictures and shelves than for lighting a whole room.