Website Search Qualifer

Good afternoon all.

I am looking for a good web applet that will allow me to put a search qualifier onto a website. “Search Qualifier” is the only way I can think of to describe it and may not be the correct term for it. However, an example would be on Newegg’s website on their left navigation bar. At first it shows all the examples of category X (processors lets say) and then by checking off certain boxes / radial buttons your search narrows down to something very specific or a product that you are looking for. So when you are fed 1000 examples of a certain product, you can easily remove the ones that you don’t want to look at and be left with 75 examples of the more specific thing that you do.!

Can anyone point me in the right direction or if you know of a product that does this… make a recommendation?

Cheers all. Thanks for your time