Datasheet

This cable has two Micro B USB connections for when you have a "USB
On-The-Go (OTG)" device, and you want to plug in another USB device.
For example, a Pi Zero or Pi Zero W has an OTG port, as does the
Arduino Zero, and anything with an ATSAMD21 that is in USB host
mode. Also great for when you want to attach to a tablet or phone with
an OTG port.
Length: 250-300 mm / 10-12"