Concord Keystone's Eco MarineCase offers impressive protection

Concord Keystone's $40 Eco MarineCase is slim, easy to use, and waterproof up to 20 feet (six meters). Did I say waterproof? Yes, yes I did. By virtue of this waterproof design, the company says the Eco MarineCase is also rain-, snow-, and sand-proof.

The case is actually an impressive bit of engineering. When I’ve reviewed other waterproof cases, such as the RainBallet and the LifeProof, I've had significant complaints about the hassle involved in putting them on and taking them off your phone. The Marine case, on the other hand, is a snap to use. Or, more accurately, a pull and a twist. The one-piece case hinges open vertically; to unlock it, you pull down on a tab on the top-left of the case, and then twist the top edge of the case 180 degrees—that’s all it takes.

The Marine’s clear, screen-protection area has a jelly-like feel to it, and because there’s a little space between that layer and your phone’s screen, you occasionally see bubble-like areas as you press on the screen. But this isn't a significant annoyance—the bubbles are barely visible when the screen is illuminated. Similarly, sliding your finger across the screen isn’t nearly as smooth and frictionless as on a naked iPhone’s glass, but you can certainly use your touchscreen as needed. This clear front covers the iPhone's Home button but, again, since the screen cover is so squishy, pushing that button through the case is easy.

On the other hand, you can’t use any of your iPhone's other hardware buttons and switches while it’s clad in the Marine. The rest of the case is made of rigid plastic, and the dock-connector port, headphone jack, volume buttons, Ring/Silent switch, and Sleep/Wake button are all completely covered—not surprising, given that the case is meant to be waterproof.

The iPhone's speaker works reasonably well through the case, but microphone's performance is on the wrong side of acceptable. I successfully conducted phone calls with the case in place, but the folks I called reported that I sounded very, very quiet. If I yelled and they turned their volume all the way up and held their phones to their ears, they could hear me, but you wouldn’t want to conduct serious, phone-based business with your phone in the MarineCase.

Keystone recommends that you test the MarineCase's waterproof seal before subjecting your iPhone to dangerous conditions. In my testing, the inside of the case remained bone dry when submerged in a sinkful of water. With my iPhone inside, I even successfully FaceTime’d a Macworld colleague while the phone was submerged.

The MarineCase is available in black or white and ships with a neck lanyard. The case weighs 4.2 ounces, and measures 5.75 inches tall, 3 inches wide, and 0.75 inches thick, so it does, as all waterproof cases do, add a bit of bulk.

If you need access to your iPhone in snowy, sandy, or wet conditions, the MarineCase is an excellent option—unless you make a lot of phone calls. For the occasional shouted conversation, coupled with plenty of touchscreen use, the MarineCase fares well. It’s also an excellent option for shooting underwater photo or video.