Which Dell laptops come with Intel Wireless Display (WiDi)?

Hi,

I bought an Inspiron 15R laptop. The salesperson said that it came with Intel Wireless Display (WiDi), This is the second time I have bought a laptop from Dell where the salesperson said that the laptop came with Intel Wireless Display (WiDi) and it didn't.  Which Dell laptops come with Intel Wireless Display (WiDi)?  The sales people obviously don't know and don't know how to look it up either. How can I look this up?

Thanks.