16GB Total memory using 2pc of 8GB DDR4 , 2133MHz , CL14 , 1.2V , Unbuffered 
Lifetime warranty for exchange. by Computer Memory Solutions
Brand Computer Memory Solutions
We don't use Generic modules to avoid incompatibility issues. 
Guaranteed to work or you get all of your money back including shipping.
Features
Compatible with Dell Alienware x51 R3
Max memory 32Gb
sockets 4