4th Gen USB Data Blocker, Juice-Jack Defender Protect Against Juice Jacking, Mobile Security Gadget Purchased by White House to Protect its Employees and Networks (Multi-Color, 2 Count)

It charges my phone. I opened the case to verify that the data pins (which are present on both sides) are not connected. See the photo and circuit diagram. On the power source side, the data pins are not connected. On the device side, there are a couple of voltage dividers that will apply a voltage to the data pins. I assume that this is needed, at least in some cases, to tell the device that this is a power source or something like that. I see that on other charge-only device listings, they only show that the power side data pins are missing, so I suspect that this is a standard technique. If you are really paranoid, you might think that these four resistors (I verified that they are at least resistors) could have something nefarious hidden inside them. I don't have the means of verifying that. You could replace them with your own resistors if you really want to be sure.

Should've looked harder. I have USB-C's everywhere and will now have to either return these or buy a USB-C to USB-A adapter. Believe I'll go for the former.