The MR16 GU10 is a rarity with it's ability to dim from 100% to 25% (or lower if the load on the circuit is high enough).

• Uses powerful CREE LEDs
  
• Works across a wide input voltage range of AC220-240 and AC110-130
  
• Replaces traditional 35W halogen MR16 (GU10)
  
• 30,000 hour lifetime (longer if in a suitably air-conditioned environment)
  
• Available with 35 degree lens angle
  
• Triac dimmable