The Spherum has three intensities, which you toggle by simply clicking on it (no chat commands to remember...)
The Spherum is modifiable, so you can resize it, apply textures, and change the color of the light emitted by simply changing the color of the prim.
You could even change its shape, but then the name "Spherum" would just simply not fit anymore...
Available in copy/no transfer and no copy/transfer at the following locations:
http://slurl.com/secondlife/Gwarl/33/28/751
http://shop.onrez.com/Lance_Corrimal
http://www.slexchange.com/modules.php?name=Marketplace&MerchantID=18266