Memory Upgrade: Planning to Use Different RAM Model
As stated in Apple's technical specifications your machine officially only supports 8GB of memory total.

That said Other World Computing runs a massive on-site lab and has confirmed that the Late 2011 MacBook Pro can support 16GB without any stability issues. The memory does need to be PC3-10600 DDR3 1333 MHz however. You can find that memory available from Other World Computing as well as from other online retailers.

Do keep in mind however that, since it's an unsupported configuration, Apple won't support your machine with those memory modules installed (should you ever need to take it to the Apple store).