Sylvania RefLED Retro MR11 GU4 2.5W 3000K 36° 12V – glass body, replaces 20W

MR11 size with a GU4 base — a unique combination

The dimensions of most GU4 spotlight bulbs are:

• Standard MR16: 51 mm diameter, GU5.3 base — most common
• This Sylvania specialty model: 35 mm diameter (MR11 size), GU4 base — less common
• Standard MR11: 35 mm diameter, GU4 base (4 mm pins) — different

This Sylvania model is suitable for luminaires that have:

• A GU4 base but a bulb socket smaller than 51 mm
• Special-purpose luminaires (e.g., imported from the USA)
• Vintage and retro-style luminaires where the small bulb size is part of the aesthetics
• Smaller spotlights and display cases

Check the bulb dimensions before ordering — measure the diameter of your existing halogen bulb to ensure compatibility.

20W replacement — for small mood lighting

This bulb matches the luminous efficacy of the old 20W GU4 halogen bulb — meaning its low power makes it particularly suitable for mood lighting and decorative luminaires:

• Small spotlights and display case lights
• Mood lighting in restaurants, hotels, and cafes
• Chandeliers and decorative luminaires where the overall brightness is created by several bulbs together
• Table lamps and night lights
• Maintenance of older equipment luminaires

If you need more light from a single bulb, consider the Sylvania RefLED Retro MR11 GU5.3 4W model (345 lm), which replaces a 35W halogen bulb.

Requires a 12V transformer

This is a 12V low-voltage bulb that requires a 12V transformer to operate. This Sylvania model is compatible with both:

• Magnetic transformers (traditional, heavier) — common in older luminaires
• Electronic transformers — lightweight, more modern technology, found in almost all new luminaires

Compatibility with electronic transformers depends on the exact transformer model — not all may work with this LED bulb. The most common compatible brands are Helvar, Tridonic, Osram, Ledvance, and Vossloh-Schwabe.

You can find compatible transformers in the Electrical accessories → Transformers category.

Check the transformer power

The transformer power must match the bulb (or the total power of several bulbs). For a single 2.5W bulb, the transformer can be a minimum of approximately 5W (leave a small reserve). For multiple bulbs:

• 5 bulbs = 12.5W → transformer at least 15W
• 10 bulbs = 25W → transformer at least 30W
• 20 bulbs = 50W → transformer at least 60W

Glass construction — premium quality

Unlike standard plastic LED bulbs, this Sylvania RefLED Retro has a full glass construction — the same material as traditional halogen bulbs:

• More even light distribution than plastic
• No yellowing over time
• Halogen-like appearance — fits seamlessly into older luminaires
• Withstands higher temperatures than plastic

Replaces a 20W GU4 halogen — 87% energy savings

This 2.5W LED produces the same luminous efficacy as a traditional 20W GU4 halogen. Energy savings are approximately 87%, and the lifespan is:

• 20W GU5.3 halogen: 2,000–4,000 h
• This Sylvania RefLED Retro: 15,000 h — 4–7 times longer

Additionally, 50,000 switching cycles make this an excellent choice for luminaires that are frequently switched on and off (e.g., motion sensor lights, bathrooms, warehouses).

This bulb is non-dimmable

Do not install the bulb in a luminaire equipped with a dimmer. The bulb may flicker, stay on at full power, or be damaged.

36° beam angle — wide spotlight

This bulb's 36° beam angle is flood-class — a wide spotlight that is suitable for:

• Mood lighting in hotels, restaurants, and bars
• Small spotlights and display case lights
• Chandeliers and multi-bulb luminaires where the MR11 size is suitable
• Maintenance of older equipment luminaires

Installation checklist

1. Check that the luminaire has a GU4 base (not GU5.3 or GU10)
2. Measure the diameter of the bulb socket — a 35 mm space is required (not a larger MR16 space)
3. Check that a 12V transformer (magnetic or electronic) is in use
4. Check that the transformer power is sufficient for the total power of the bulbs
5. Check that the luminaire does not have a dimmer
6. Turn off the power before installation — do not touch the glass of the bulb with your fingers
7. Install the bulb in place and turn on the power

Also check out other GU4 LED spotlight bulbs in our selection.