here is a link for Night White:
http://www.smilox.com/smile/nitewhiteinfo.cfm
I have the 22% concentration
It cost me $350 cdn the first time around (since I had to pay for the custom fitted trays + 6 syringes of gel). When I need gel refills, it comes in a package for 3 and I think the dentist said that was $30. The instructions for was to wear it twice a day for 30 mins each time, for 2 weeks. I can repeat again in 6 months.