Title says it all I'm confused to say the lease I must be missing something they look the same, the 3106 is cheaper. Whats the difference??

Download the specs here:

http://www.lutron.com/pdfspecs/366-580.pdf


On page 10, it explains that the 3500/4500 series can be programmed using the Grafik Eye Liaison software. Everything else is the same, meaning it can be retrofitted in place of a 3100/4100 unit.

Ahh that explains allot so if I don't need the computer program option then I should grab the cheaper 3100/4100. Thank you for the information.