If it helps, this is my attempt at a not-actually-Photoshop overlay:
For rough scale use the hand, or other posters' suggestions of !L saucepan or just under 5in diameter.
There are repeated posts about looking for "memory card" (or similar) - those are just misleading. If the CSMU has worked as designed then the memory cards will still be sealed inside it, it is finding the unit now it is separated from the chassis and ULB that is the problem. I've never handled one either, so I don't know how much they weigh, but given what they are specified to withstand they won't be exactly light (1kg or slightly more maybe?) - gut feeling says a 1kg round projectile may penetrate whatever it lands on a lot further than that flat chassis.