TK-421 iPhone Case with Flip-out Keyboard Review

Finally, an iPhone with a physical keyboard! Some of us have been waiting for this day since June of 2007. ThinkGeek is the first to endow iPhone with such a feature. The TK-421 iPhone Flip-Out Keyboard is a case for your iPhone 4 or 3GS that uses bluetooth connectivity to give iPhone the 36+ buttons you’ve been craving. The keyboard works universally for all iPhone apps. So, the big question: how is it? Dive in to find out….

About the Design

Apple’s iOS 4 update enabled the use of bluetooth keyboards on iPhone 4 and iPhone 3GS (sorry iPhone 3G, you’re not fast enough). That’s how the TK-421 works; it does not need to connect to iPhone’s dock connector. The TK-421 has its own battery and comes with a Micro-USB cable to charge it. The TK-421 is one piece with two parts: the bottom half is a bluetooth keyboard, and the top half is regular iPhone case. These two parts are attached by a hinge that swivels. The swivel is not spring-loaded (like a sidekick), but it has magnets to lock it into its open and closed state. The user manual states that the magnet will not affect wireless signals, but can affect the compass.

TK-421 is lighter than you’d think. It weighs less than two and half ounces. The case is pretty plasticky and has a flimsy feel that’s caused by a gap between the two parts of the case. The swivel hinge does not seem super durable, though it’s apparently durable enough to support the weight of iPhone. The iPhone housing has cutouts for all buttons, ports, and the camera too. To insert iPhone, squeeze and slide the bottom off of the case. TK-421 for iPhone 4 is more than twice the thickness than twice the width of iPhone 4.

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The Keyboard

The keyboard is big and well spaced. It’s very large for a mobile keyboard, but not overly large. There are 49 keys, 5 rows of 10 (space is two keys wide). The keys are plastic and have a good click feedback; we preferred this to the rubberized keyboard. We like that all numbers and letters have dedicated keys, as do space, period, comma, semicolon, shift, and slash. We also like that there are arrow buttons, multimedia buttons, and a lot of special characters. They are accessed using the function (Fn) or shift buttons. We don’t like that the backspace is on the bottom next to the space button. We also don’t like that certain functions don’t work like brightness, expose, escape, menu, home, end, insert, and print screen. The multimedia control features were convenient to have, they include play/pause, track back/forward, and volume up/down. We made the discovery that the keyboard aspect of this case can actually be purchased, standalone, at DealExtreme.com–which explains why there are functions on it that don’t work.

Using TK-421

Syncing the Bluetooth keyboard was a pretty easy process; it works just like pairing any other bluetooth device. Once the keyboard is paired you can start typing, regardless of whether or not iPhone is in the case. If your phone is in lock mode, a key press will automatically unlock it. The typing works in all applications, anywhere that the virtual keyboard works. When you begin typing the virtual keyboard disappears, maximizing your screen real estate. Unfortunately, in most cases the enter key functions as a carriage return rather then an enter button, but this is a limitation of iOS, not the keyboard. It’s comfortable to type on, both with one hand or two. Though it would be tough for people with smaller hands to successfully type with one hand. The large keys make it easy to type accurately and quickly. iPhone’s autocorrect still works, and sure helps. The hinge on the side makes it awkward and uncomfortable to use when the case is closed. It’s still possible to type and use your phone in closed mode, it’s just not optimal—the hinge juts out relatively far from the case. TK-421 has an On/Off button hidden on the back of the case; you never really have to shut it off, as it goes to sleep mode after a couple minutes of no use. To conserve battery on your phone, don’t leave Bluetooth running all the time.


Is the TK-421 iPhone Flip-Out keyboard what we’ve all been waiting for? Probably not. TK-421 is a pretty bulky case, and thus makes regular tasks on iPhone more cumbersome then usual. It is, however, a great accessory to have for iPhone. If you know you’re going to be doing a lot of typing on your 3.5” screen, then it’s ideal to maximize screen real estate and use a portable keyboard that’s easy to type on. The TK-421 costs $50 from Thinkgeek.com, which is a pretty reasonable price for what it is, even if you’re going to just use it as an accessory. If you’re in dire need of a physical iPhone keyboard, this is not a bad purchase. Alternatively, you could wait it out for a few months; since we’re most likely going to be seeing more and more of these keyboard cases hit the market.

The Good: Good keyboard with multimedia keys and special characters, easy to type on, light, inexpensive, maximizes screen real estate.

The Bad: Bulky, Hinge is large and awkward, flimsy feeling, optimized for landscape use only (not portrait)

One Comment

  1. I have the DealExtreme version and while the layout is similar, it’s not actually the same thing. The DX version has rubber keys – if you look at the magnified photo on the DX page you can see the texture of the rubber.

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