Ultra compact energy saving CFL lamps with triple-tube design give an ideal light source for small fixtures and downlighters. Biax™ T lamps allow more compact fixture designs with the same lumen output as Biax™ D lamps. They can also be used to deliver higher lumen output from existing designs. The Biax™ T lamps are electrically interchangeable with Biax™ D and D/E lamps.