Anyone tried lens attachments on z3

Hi guys,

I was going through Amazon for external lens attachments for my z3.
So I wanted to know if someone here has tried it and can share his experience.

these are the links I thought within my budget.

http://www.amazon.com/First2savvv-JTSJ-YY-A16-Universal
http://www.amazon.com/First2savvv-Universa

So please let me know if they are worth the buy if you know about these things.