I use velcro tape, and then if possible a cable tie around the ESC. This serves two purposes:
- It helps keep the ESC on the mount
- It holds the case together, as the MMM case is not screwed together, they have been known to come apart.
That's about it really. Though I have only been running velcro tape recently as on the Hyper 9E there is no way to fit a cable tie, and it hasn't fallen out yet (done 2 race meetings with it like this). Touch Wood!
I would really recommend the velcro tape that Ripmax sell, it comes in very wide strips and has excellent adhesive.