I recently acquired a 3" SF turbo head and installed it on a mod that
had a KT turbo head:
The 1 Watt SE over driven at 660 mA is the same turbo module and McLux power pak
discussed at : 1Watt Turbo.
The beam shot below has the same LED module and Li-Ion battery (Copia 168B) shown
on the left being projected through a KT turbo head and on the right, the 3" turbo head.
At 1 meter, Lux readings of 3400 and 5110 were taken respectively. At a distance,
there is much less divergence with the 3" turbo head and the "throw" is significantly
further, resulting from the narrower beam angle.
With the less massive 3" head, lexan lens and lithium battery, this flashlight is surprisingly
lightweight!