These allow iOS devices to work with class compliant USB devices, such as audio and midi interfaces, and access media (from iOS 13 onwards) without the camera connection kit. It's not possible to charge the iOS device with them.
Tested successfully with Sonosax SX-M2D2 and Sound Devices 8 Series
15cm and 1.2m variants available
Manufacturer has stated this is incompatible with FiiO M11 and Shanling UP2 DACs