Typing without looking down on the keyboard requires a degree of mastery that even the best of touch typists can't always accomplish!
With the Tap finger keyboard though, you will never have to look at your hands while typing on a keyboard again.
Tap looks like something out of a sci-fi movie, being a rather unique type of keyboard that works via finger gestures as opposed to laser projection virtual keyboards which project a keyboard for you to type onto space.
Tap is a five-ring strap that slides over your fingers with the thumb-ring being the brains of the unit. Tap features haptic vibration feedback to alert you when battery is low.
The thumb ring features a single button for turning on and for activating pairing mode. The five rings, which are connected to each other via a thin wire hidden within the strap's fitting cable, integrate a 3-axis accelerometer each.

Tap registers keystrokes by measuring the deceleration of your fingers as they come in contact with a surface, which means you can't use Tap to type in the air so you need a solid surface, preferably a hard surface for better response.
Tap connects via bluetooth 4.2 with a transmission distance of 10 meters in direct line of sight. When connected to a device, Tap is registered as an input device.
From the companion app, called TapManager, you can adjust settings. Tap is multi platform so it works on iOS (version 9 and newer), Android (version 5 and newer), OS X Yosemite(version 10.10 and newer), Windows (8.1 and newer) and Linux Ubuntu.
Rather than distinguishing letters based on your fingers' locations, Tap assigns each letter or number its own unique gesture that you have to remember.
While you don't have to look at a keyboard, Tap requires time to learn a completely new way of typing because of the multiple finger gestures involved.
The easiests taps are single and double taps. Common vowels (a, e, i, o, u) use single taps, while common consonants (n, t, l, s) use double taps.
More complicated fingers gestures include alternating taps between several fingers to bring up numbers and keyboard functions; hence the learning curve.
Luckily though, Tap comes with finger gesture shortcuts to make typing faster. For instance, double tapping your middle finger brings up the letter j, while tapping the last three fingers brings up the numpad function.
To help you learn to use Tap faster, you want to use one of the training/game apps, including TapAloud, TapGenius Game app, TapTapBunny Game, TapChase Game, TapSquadron Game, TapLoops Game and the TapTutor App.
The training/game apps are all available on Google Play Store and the App Store and gradually introduce the gestures and then drills the gestures into your muscle memory.
With the help of the training apps you can get typing slowly 10 words per minute in about 2.5 hours and become faster as you get used to it. With that said, you won't be able to type with Tap as fast as with a normal keyboard so that is something to bear in mind.
Tap is ambidextrous so it works on both left and right hand fingers. Once you learn to tap with one hand, you don't have to relearn with the other hand which is odd but a testament to how well the training app works.
Tap works as good as you do a good job of typing; hence practice makes perfect. Tap is lightweight (45-50 grams) enough to be worn comfortably over your fingers or gloves and its built-in 3.7V 45mAh battery lasts 8 hours (7 days on standby and 2 hours to recharge ).
You can bump up the battery life of Tap to up to 64 hours when using the included case which doubles as a 370mAh powerbank charger. The Tap case measures 165mm long, 44mm wide and 41mm tall and weighs 100 grams.
As well as a keyboard, the Tap keyboard strap works also as an optical laser mouse with very little lag. The built-in mouse is switched on by laying your thumb down and moving your hand around to move the mouse cursor.
To scroll up and down a page, you lift your fingers and to enter continuous scrolling mode you tap your ring and pinky fingers. To drag and highlight text, you tap the ring and middle fingers.You can adjust the sensitivity of the mouse via the TapManager App. ​
The Tap firmware is updated regularly, which is good to know as it means Tap is being improved so it can only get better with time especially the detection accuracy of tapping. UPDATE 26 MARCH 2020: See Tap Strap 2 review. Buy it