I bought mine primarily for daytime visibility. You can clearly see the difference between stock incandescent bulbs and LED bulbs.<br />
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In this pic, I've swapped out the left passing lamp for an LED unit. The right passing lamp and headlight are still the original OEM bulbs:<br />
<img src="http://img.photobucket.com/albums/v59/hd_rider/Trike/Lights_01.jpg" border="0" alt="" /><br />
<b><font size="1">(click on picture to see full-size image)</font></b><br />
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After all three bulbs have been converted to LED:<br />
<img src="http://img.photobucket.com/albums/v59/hd_rider/Trike/Lights_05.jpg" border="0" alt="" /><br />
<b><font size="1">(click on picture to see full-size image)</font></b><br />
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As a side note, I always run with my high-beams on during the day and I've wired my passing lamps to illuminate regardless of the high-beam switch.