Thanks to iPhone cases, we can turn the back of our phones into everything from an 80s-style cassette tape to a British phone booth…there’s even an iPhone case that’s shaped like a big pink rubber ear. Even that gets old after a while. There are only so many iPhone case designs out there and, besides, cases add bulk.

Enter the new trend in iPhone customization—rear panels.

Since Apple only gives us two choices in our iPhone design—black with the Apple logo or white with the Apple logo—we’re getting restless for a new look without having to add bulk. So if you’re handy with a screwdriver and willing to do a little assembly, rear panels may be just the customization you’re looking for. So far this is a relatively new offering, so there aren’t as many choices as you’ll find in cases, but here are a few of the more notable offerings. Prices range from $14.49-$29.95.

However, be aware that removing the back plate of your iPhone will void its warranty.

I’m not saying I recommend it, but if you’re feeling pretty daring, you can find plenty of how-to’s online. You might want to heed this warning from TechRepublic’s Bill Detwiler first, though.

I thought removing the plastic antenna cover was difficult,” Detwiler wrote. “It was child’s play compared to removing the iPhone’s back case panel.”

He went on to detail the process he used, which he said took more than thirty minutes.

But CNET’s Sharon Vaknin has a different story. She claims replacement is easy and the site has a video to show you how.

Installation is simple, and requires just a replacement backplate and a Philips screwdriver (or a pentalobe screwdriver for the newer iPhone models),” Vaknin wrote.

She, too, pointed out that removing the rear panel voids the warranty, so you may have a tough time getting Genius Bar support with your new rear panel in place.

But if you’re ready to tackle the challenge—or if you’ve broken or cracked your iPhone’s rear panel and need to replace it anyway—here are a few back panels that can give your iPhone 4 or 4S a facelift.

• Mirrored rear panel— If you’re like me, you only carry your phone, your keys, and your wallet along with you, which is fine until you’re worried whether or not you have parsley stuck between your teeth. iFixIt turns the back of your phone into a mirror, doubling its usefulness. A separately sold Baller Suction Cup attaches safely to the front of your phone, letting you prop your phone up for use as a desktop mirror while you work.
• Gunmetal—This grey metal back claims to be both nice to look at and more resistant to scratches than the iPhone 4’s glass back. Interest in metal back panels began when Apple warned in 2010 that some third-party cases could scratch the iPhone 4’s sensitive back cover if particles became trapped between the two surfaces. Third-party manufacturers took this as a cue to create something that could withstand something as simple as a dirt rubbing up against it.
• Red back panel—Red isn’t a color available in the iPhone 4 or 4S…and the cases that mimic the iPhone’s look in red are flimsy and have a cheap feel and look. This back panel turns your black or white iPhone into an eye-catcher.
• Piano Pattern Glass—Ideal for the musician or music lover, this rear panel jazzes your iPhone up (pun intended) with its black and white piano keys. And because it’s made from glass, it gives your iPhone the same feel you have with the original case.
• Transparent panel—This one’s a real puzzler to me. It is truly transparent, allowing you and everyone you meet to see exactly what is inside your iPhone. Why anyone would want to do that is beyond me—maybe it’s more for someone who is an ultimate techie, but to me, once I have my iPhone rear panel out and have seen inside it, I don’t really want to spend the rest of my time with that phone looking at its guts. But if it sounds like a fun idea, give it a try.

I don’t know if this is something I’ll attempt, since I tend to like my case for now, but I can see this being popular with iPhone owners. If I were ever to damage my iPhone’s rear panel or, say, out of my two-year contract so I could get a new one if I happened to break something, I would definitely give it a try.