If you are using extension cords for USB cables or other data cables it is sometimes handy to use something that:

• prevents loosing the connection
• protects it when you are accidentally stepping on it
• makes it better visible to prevent stepping onto it in the first place
• takes the strain of the connection if you are pulling on one side of the cable...

and probably some other things more...

I designed a (on purpose) not so small box - to do just that.

The fit is pretty tight and I added some dimples to prevent the casing from accidentially opening.