Pros
Widely available at most hardware stores.
Flexible design allows gradual bends without specialty couplers.
Offers good protection from vandalism, weather (rain, hot/cold conditions and UV exposure), wildlife, and accidental damage.
Connects to Wasp Mounting Boxes and Marshall Mounting Boxes without adaptors
Hornet Mounting Boxes with additional adaptor
Easier to cut and form than EMT (Electric Metallic Tube) conduit.
Easily connects to Electric Metal Tubing (EMT), several connector options
Cable is able to be pulled through in most cases.
Challenges
Will still require adaptors for tight bends.
Can be cut with bolt cutters, but not much else.
Difficult to make right angles and straight lines (more unsightly).
When to use FMC
Complex exterior bends
When cable protection is needed
When connecting individual runs from the mounting boxes to EMT
Tools/supplies needed
3/8 in flexible metal conduit (for single cable runs)
One or two hole strap fitted to the size of conduit you are using
Fasteners for the surface you are mounting to
Step by Step Installation Instructions
Measure to length and cut conduit using overcompensate for any unexpected bends you can cut more off if needed.
Run cable through conduit
Using the straps and fasteners secure conduit to surface
Use compression couplers to secure conduit to the mounting box, some larger mounts may require a threaded clamp connector. A good way to make sure you have the right adapters and connectors is to take any mounting boxes with you to your local electrical supply store.