but you can also get these cheep ones off amazone .. but i dont know how well they work , ive seen some good reviews
http://www.amazon.com/Dimmable-Switchable-Electronic-Digital-Hydroponic/dp/B0052ACH0E/ref=sr_1_1?ie=UTF8&qid=1326747771&sr=8-1
^^ it looks decent and its dimible/switchable :)...