GE NX-10 Installation Manual page 158

In order to mount other modules (for example, NX-216E or NX-507E/508E):
Drill 0.3 mm holes for the card guides in the box.
1.
Figure 21. Drilling holes.
Place the card guide in the box.
2.
Screw in the card guides.
3.
Figure 22. Placing card guides.
Use the card guides to mount up to 3 further modules. Check the relevant module chapter
4.
for wiring and programming information.