Hortilux PowerVEG is different than other T5 lamps. Not only does it produce a well balanced spectrum for your plants, it also provides UVA and UVB. UV is an essential component of the spectrum that produces stronger, healthier plants, allowing them to produce higher quality fruits and flowers. The sooner you introduce UV to your plants, the better your end product. No other T5 bulb on the market produces a spectrum with this quality or UV of any kind.Why PowerVEG is like no other T5: First and only T5 to incorporate full spectrums of UVA and UVB (UVA = 315nm â€“ 400nm : UVB = 280nm â€“ 315nm). Exclusive chemistry which produces UVA & UVB. What PowerVEG does for your plants. Promotes extreme photosynthesis for faster growth. Creates a stronger root system. UV light allows for easy transition from indoor veg to outdoor flowering. UV light helps develop stronger healthier vegetative plants that will produce higher yields and higher quality crops. Creates faster producing yields, vivid colors, more flowering and better tasting crops. 4 foot sizes only. See http://www.eyehortilux.com/products/power-veg.aspx for more in depth information.