Your iOS phone or tablet may not have a USB port on the bottom but that doesn't mean you can't use it to connect USB devices. Secretly known as a 'Camera Connector' or 'MIDI Connector' cable, this doohicky plugs into the bottom of your iOs device and gives you a USB A port. Then you can connect HID Keyboard, MIDI or even some Camera devices.
Please note: just cause you have a USB port on something doesn't mean it will magically work with this cable. iOS restricts USB access to only keyboards & mice (USB HID) and MIDI devices. You cannot use it with mass storage disk devices, or UART (USB CDC) devices. Also, the device must have a USB descriptor that indicates it draws 100mA or less. Many USB descriptors say 500mA even if they don't use that much!
That said, it does work quite nicely if your device is HID or MIDI only and has the USB 100mA descriptor thingy. Our SAMD Arduino core, for example, has this fixed so you can connect a Circuit Playground Express programmed as a keyboard or for using MIDI on your iPad with NeoTrellis!
At this time, both MakeCode and CircuitPython don't have the correct descriptor fixes.
Approximately 6.5" long from end to end. Tested working with iOS 12 and an iPhone X, but should work with any lightening port iOS device.
Total length (including connectors): approx 165mm / 6.5"