M-VAVE 25 Key USB MIDI Keyboard Controller With 8 Backlit Drum Pads, Bluetooth Semi Weighted Professional Dynamic Keybed, 8 Knobs and Music Production

It has poor instructions. You need software and sound source. In my case it links perfectly with Garage Band. Amplification will come from your phone -tablet-or Computer. Cost is fabulous. Small 1/2 size keys

The M-Vave (also known as M-Wave) 25 is very reliable for me and I use it as my main midi keyboard because the bluetooth and light weight is important in my compact, small space. It has an internal rechargeable battery that holds a charge fairly well. I don't use all of the features other than octave and arp, so I can't attest to all of the functions, but those work great. The keys feel pretty basic nothing special about them, but that doesn't matter for me. I like the way the keyboard looks it has a nice matte finish, with cool lighting colors that look good next to my Razer computer keyboard. I've dropped it on carpet a few times and bumped it around on a shelf and it is sturdy and held up. There is a software it comes with it's a bit difficult to find it on their website but it is there to connect with your PC and configure the features. But you can also use Midimittr on iOS (ipad) free in the Appstore works fine, or the Korg Bluetooth Midi Connect, that's how I use it for connecting to iPad. I think if you really value light weight and easy ergonomics you might like this keyboard. These preferences are something you only discover in time if you're new to making music, but after routing cables on a set up and moving synths around for a few hours, you will appreciate this light, compact mobility of the SMK 25 bluetooth no cables or wires!