Will this RAM work with my iMac?

Hello Apple Community!

Just a quick qestion to see if this RAM i have selected would work on my iMac.

Im sure this question comes up a lot but i really dont know anything about RAM and as the iMac cost me a lot i want to make sure i have the correct one selcted.

RAM link - http://www.amazon.co.uk/memory-upgrades-4GBx2-1333MHz-Macbook/dp/B004TQH6U8/ref= pd_cp_computers_1

No idea if this infromation is helpful but im going to post it in case.

iMac specs;

Mid 2011 iMac 21.5" - 2.5Ghz - 4gb RAM - Intel i5

Screenshot if it helps;

[IMG]http://i46.tinypic.com/a2vv5f.png[/IMG]

Many thanks, Josh.