This is a holder for an Amazon Basic USB 2.0 Extension (https://www.amazon.com/AmazonBasics-Extension-Cable-Male-Female/dp/B00NH11R3I). Got tired of having to pull back our iMac to plug in a usb drive, or people forgetting to take it with them, so hopefully this will mitigate that. You'll need to remove the "Amazon Basic" label with a sharp knife or small flat head.

To install, you'll need to press the female end up and out from the bottom through the front at a steep angle, about 1/4" till the back part of the female end clears a lip inside the holder. Once the female end is flush with the top part of the inner space, then press it in till it's seated into the holder and flush with the front.

Also uploaded the Sketchup file (.skp) if you want to add any labels or text to the front like I did.