Hey,
Randomly I saw this topic and it is also a subject which I'm interested in...So check this;
In the explaination of products,it is telling what this new "Dual Spectrum" technology is...
http://www.greenshorticulture.co.uk/Grow-Lights-182/Grow-Lamps-192/Dual-Spectrum-Grow-Lamps-806.asp
See u..