Specifications fresnel lenses

[gelo]

Hi,
which are the specifications of this lenses?
I want to buy it from an Italian vendor...but what must I say at the vendor? The fresnels lenses are not all the same....right?
I don't refer at the focal length but the material etc...
Thanks

Luca

 

[gelo]

Ok, my english is bad 🙄

I change the question. I have an 15" LCD and I want to buy a triplet lens. I have found this site Izzotek
The fresnel lens have 214/326mm focal length (link)
What of these projection lens I should buy:
- 300mm
- 345mm
They sell a "Varifocale 310/360mm"... can i use this lens in my project?
Thanks

Luca