A Closer Look
The sticker on each module has the model number. There you will also find the info about speed, voltage needed and what the kit is rated for in terms of CL rating.
With the modules installed, they certainly have a demanding presence. Take special note that with the memory socket layout of the ASUS Maximus Formula, it is not possible to fill the remaining two sockets due to the thickness of the Flex II heatspreaders. This should not be a major issue for anyone however, considering the kit already offers 4 GB total. Additionally, other boards may have a wider memory socket layout that would permit use of the remaining two sockets.