This cable is a little unusual, rather than having a USB A plug on one end, it has two Micro B USB connections! What is this for? It's 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 a 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.
Sure, we have OTG adapters, but this is simpler, no extra cable required
It's about 25-30cm / 10-12" long, so it's nice and compact. Note that the ID pin is connected to ground to 'force' the host into OTG mode!
- As of Oct 20, 2019 we have the ID pin on the MicroUSB connector tied to GND on both ends, this will help some hosts to force them into OTG mode
Please note, the wire colors inside the cable may not be the same as indicated in the datasheet. This does not affect functionality and you'd only see the colors if you cut the cable in half.