I preordered my first pair of WIDI Masters when they were still under development. They promised the ability to connect MIDI devices wirelessly without a third device, like a computer or tablet. It seemed too good to be true, but I was willing to try. I was not disappointed. I now own seven WIDI Masters and use them both live and in the studio. As a heavy MIDI user, they are amazingly useful tools. I keep finding more uses for them.This is one really important difference between WIDI Master and many of the other WIDI dongles you'll find here and elsewhere. Most of those others, such as the Yamaha MD-BT01, can NOT connect to other Bluetooth WIDI devices. They can only connect wirelessly to a computer, tablet or phone equipped with Bluetooth MIDI. In other words, you can't connect two such devices together. WIDI Master CAN wirelessly connect to almost any Bluetooth MIDI device, including other WIDI Masters. To put it simply, with two WIDI Masters you can connect any two MIDI devices (with 5-pin DIN connectors) wirelessly, without having to go through a third device. Essentially you use them just like MIDI cables--but without the cables! This is a really big deal. Nothing like this existed before WIDI Master. It's a game-changer.I've been using these little MIDI miracles in many ways. In my photo, you see three WIDI Masters plugged into my studio MIDI interface. I use these to connect (from left to right) a Korg nanoStudio controller, a Roland Aerophone Pro, and Roland SH-201 synthesizer. In my live rig, I use WIDI Master to connect two of my three keyboards directly to my iPad for changing patches via app (OnSong). I've even used WIDI Master to connect a set of Roland V-Drums to my studio from another part of the house. I could go on, but suffice to say these things have made a huge impact in my MIDI life. The things I'm using them for didn't even seem possible a few years ago. Now I don't know how I lived without them.Operating them can be remarkably simple, depending on your situation. In the most basic situation--for example, connecting two MIDI keyboards together--you simply plug them in. The devices will automatically connect to one another, and you're good to go. That simple. But things can get a bit complicated with more devices. With multiple Bluetooth MIDI devices in the area, managing which devices connect to one another can be confusing.Fortunately, CME has developed an app to control your WIDI Master setup. I highly recommend using the app to update the firmware on your WIDI Master before using it. You need to plug your WIDI Master in to power it (it gets power from the MIDI OUTPUT of any MIDI device). In the app, you'll see the device and be able to connect to it. Once you've updated the firmware, you'll have the ability to manage your settings. You can set a WIDI Master to "peripheral" mode. This prevents it from accepting connections while still allowing it to connect to other WIDI Masters. You can also create groups of devices that always connect in the way you need them to connect. These are incredibly useful features if you have many WIDI devices like me.To sum it all up, WIDI Master is an amazing little MIDI miracle that lets you connect almost any MIDI device to any other MIDI device wirelessly. It simply works, and works better than I'd thought possible. It's not an exaggeration to say these devices changed my life.