1747 L40a

I have this PLC and was wondering if anyone was familiar with what goes in the space under the memory module? It has # 40845-940-02

I'm not aware of anything under the memory module. Facing the controller, in the upper-left hand corner is the battery, power fuse underneath it, Jumper J2 to the right of the battery connector and the memory module under J2. Here's a link to the user manual; the picture of interest is on page 4-6:
http://literature.rockwellautomation.com/idc/groups/literature/documents/um/1747-um009_-en-p.pdf