Tech21 Impact Herringbone smartphone case

A smartphone case that uses D3O to protect your smartphone from being damaged when dropped

Tech21 Impact Herringbone smartphone case
  • Tech21 Impact Herringbone smartphone case
  • Tech21 Impact Herringbone smartphone case
  • Expert Rating

    4.00 / 5


  • Protected the Galaxy S4 from shattering when dropped from 1.2m onto hard tiles, and from 60cm onto a wooden structure


  • Can be hard to press the power button

Bottom Line

Tech21's protective case for the Samsung Galaxy S4 (and a few other phones) is a good one. It protected our S4 perfectly during our tests and everyday use, and it also feels good to hold overall. However, it does make the Samsung phone's power button hard to press.

Would you buy this?

  • Price

    $ 29.95 (AUD)

If you have a Samsung Galaxy S4 smartphone, you’ll want to get a case that’s capable of protecting it from accidental drops onto hard surfaces. After all, a replacement screen can cost upwards of $200! We’ve tested a case from Tech21 that can do a very good job of protecting your phone if it ever does slip out of your hands or your pocket, dispersing energy from the impact point rather than letting it all travel through to the phone.

Generally, we don’t get too excited when it comes to phone cases, but our Tech21 case arrived with a sample tub of the material that makes the case work, as well as a little mallet. The material that the Tech21 case uses is called D3O. It’s what’s known as a non-Newtonian fluid with a free-flowing structure when no pressure is applied (it can easily be stretched and formed), but its molecules lock together when pressure is applied to them. It can, therefore, absorb and turn energy away after an impact.

We’re not great with the science of it all, but that’s the general understanding we have. Basically, it’s a material that’s used in protective clothing for motorcyclists, the military, and other activity-based gear that’s designed to give protection from high impact events, and Tech21 has the exclusive rights to use it for smartphone cases.

The material is hand laid in Tech21’s cases, at the corners and along the sides. The idea is that the phone will more often than not hit the ground on one of its corners rather than flat on its back or front, and any such impact will shatter the screen. We’ve got first-hand experience of a Galaxy S4 slipping out of our pocket while we were sitting down, and the top corner has hit the concrete floor and shattered the screen. By concentrating the D3O material in the corners, this type of accident should not result in a shattered screen.

This is what happened to our unprotected Galaxy S4 when it fell out of our pocket from seat height onto a concrete floor. The Tech21 case should prevent this sort of shattering.
This is what happened to our unprotected Galaxy S4 when it fell out of our pocket from seat height onto a concrete floor. The Tech21 case should prevent this sort of shattering.

We tested the case by dropping it numerous times on a hard tile floor in our office balcony, and from a height of about 1.2m (this is shown in the first video below). This is the height at which we carry a phone during normal operation while standing. Even after a handful of drops, the phone survived without even obtaining a scratch, and it always landed on one of its corners.

In the second video, we simulated dropping the phone onto floorboards from a distance of about 60cm, again dropping it multiple times, and again it survived without any blemishes. We also dropped the same phone while it was wearing some other cases (after we tested the Tech21 case), purely for comparative purposes. (You can see that some cases like to bounce the phone a lot more than others).

To demonstrate the effectiveness of the D3O material outside of the phone case, a rep from Tech21 told us that we could wrap the raw material around our fingers and hit it hard with a mallet. On its own and while unformed, the material is gooey and easily stretched, and it doesn’t look like it can protect much of anything, let alone fingers from a mallet. It feels more like a toy than a serious product. However, when formed around an object and subjected to pressure, it should provide a solid layer of protection that repels energy from the impact zone.

The Tech21 rep told us that we wouldn’t feel anything when hammering away at our finger because of that, so we gave it a go. True to the rep’s word, we were able to hammer away with all our might without getting bruised or sore afterwards — though we’ll admit that we did feel a little pain as the material became thinner the more we hammered away. It’s the same way Tech21 sells the cases to the stores whose staff ultimately recommend these cases to customers, and it must be doing a good job because the company claims that it’s case is one of the top-selling models in Apple stores (yes, the case is also available for iPhones). Incidentally, the creator of the Tech21 case is the same person who came up with Apple’s bumper design.

As for looks, the Tech21 case is translucent and you can see the D3O material running along the edges. It has the same orange colour that can be found on high visibility vests, though it’s not reflective. We think it looks good. It’s a case that’s relatively easy to put on the phone, and it adds about 4mm to the thickness of the phone on each edge. That means it feels a little bulky, but for the peace of mind this case provides, we think it’s a fair trade off. One of the other good points of this case is that it provides some grip, which means the phone won’t easily slip off a table or out of your hands.

It can be hard to press the phone’s buttons when the case is on the phone, especially the power button. However, the Galaxy S4 doesn’t have the best buttons to begin with. We got used to the squishiness of the power button after a while and found out that we didn’t have to press too hard to get the phone to switch on. After a while, though, we stopped pressing the power button and used the Home button to wake up the phone and view our lock screen.

The Tech21 case is available from Apple stores for the iPhone 4 and iPhone 5, as well as Vodafone stores and Harvey Norman for the Samsung Galaxy S3, Galaxy S4, Galaxy Note II, Sony Xperia Z, and HTC One. Pricing starts at around $29.

You can also add more protection to your iPhone 5 or Galaxy S4 by opting to install Tech21’s Impact Shield screen protector (also for around $29), which is based on BASF polymer that can be found in bulletproof glass. This screen protector is a little thicker and more rigid than most, and provides a little more resistance than the screen on its own as you slide your fingers across it.

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