Sony E-Mount cameras introduced in 2013 and later are equipped with a new Multi-Interface camera hot shoe. It has 24 electrical contacts on the toe of the hotshoe to support external flashes and other accessories.
These electrical contacts are great at collecting dust, dirt, lint or whatever else might be inhabiting your camera bag - and that's why Sony supplies a snug-fitting cap - to help you keep this area clean.
If you've lost your hot shoe cover, you can purchase a replacement on Amazon for about $5. You wouldn't want to just leave the hot shoe uncovered.
Imagine what might happen if a blob of lint made it's home here. The next time you attached your external flash - it might mean a poor electrical contact and a flash failure. So it's a really good idea to keep this area protected. Problem is - what to do with that little hot shoe cover when the hot shoe is being used? This question inspired the ShutterBands Kit enhancement called CapTraps.
The CapTrap disks are made of 3M DualLock fastener material - with interlocking mushroom-shaped stems. Put one disk on the inside of your hotshoe, like this:
Put a second disk on the top of your camera like this:
Now you have a convenient place to store that hot shoe cover so it doesn't get lost. Just snap it on!
Your external flash also has a protective cover on the mating hot shoe to prevent the delicate electrical contacts from being damaged. You can apply this remedy there as well.
Install a CapTrap disk to the outside of the flash's hot shoe cover:
And a mating CapTrap disk to the top or side of your external flash: