Few devices use micro A, those rare times when they do and you want to connect to this is the part, well made and works perfectly. Like the latch, two prongs retaining connector once inserted.

With USB A on the other end, can connect to anything with break out boards or onto A or Micro B now popular.

These adaptor cables are EXCEEDINGLY rare and hard to find, and SparkFun has been the ONLY supplier I've found. Many other cables labeled OTG are not true OTG. This adaptor's micro end is micro-A and is rectangular and will NOT fit into the more common micro-B sockets which are wedge-shaped. (However, a micro-A socket will accept a micro-B plug, in which case, it simply serves as a regular USB port.) What's the difference? As I understand it, micro-A plugs are specifically configured with pins 1 and 2 crossed to signify to the receiving device that it is to be a power supplier, and to act as a USB host. For example, in the case of the Edison, if it boots with a micro-B plugged into it's OTG port, it assumes that you want it to be a slave device, and won't mount any peripherals on the OTG bus. But if you have a proper OTG micro-A plugged in, it will boot in USB-host mode, and detect and mount any attached peripherals.

I mistakenly bought 2 of these thinking it would be like my other OTG USB cables; it is NOT the same kind of OTG cable used for "things like tablet computers and smartphones in order to allow for USB peripherals like flash-drives, keyboards, etc. to be hooked up" as per the product description. Instead it has an incompatible rectangular plug that will wreck your device's port if you try to use it. Upon further research, it appears that this is some other standard, and not the "B" type commonly used for phones and tablets. The problem is that Sparkfun does not stock the "B" type - so it is easy to make the mistake of buying this because its the only OTG cable they offer, and in the real world, these cables are just referred to as Micro USB OTG with no A/B designation. If you Google the name of this product - even with "Micro A" designation, all the results displayed are the correct "B" type cable!. I honestly don't know what this cable can be used on; I've never seen it before, but it was a waste of a purchase and I hope this review will help others not make the same mistake that I did. Hopefully they will update the product description as well.

Micro Type-A makes some sense on a device. It's for devices that default to Host mode and provide power. Primarily, the connector exists from before the OTG spec (when ports were still either Always Host or Always Device).

Now with the OTG Spec, Micro Type-A makes little sense from a cable. Both Micro Type-A and Micro Type-B cables fit into a Micro Type-A port. Why even sell Type-A cables? They're less versatile and it just leads to customer confusion.

I'd really argue there's no business calling a Micro Type-A to Female Type-A connector an OTG cable. OTG implies using a port in both Device and Host mode (or at least in the non-default mode for the port). But a Micro Type-A defaults to host (and is host-only on non-OTG devices), while a Standard Female Type-A is always a host port. It would make more sense to title this a "USB Host Cable Female A to Micro A".