Lenovo’s Motorola Moto Z and Moto Z Force, the newest members of Verizon’s Droid family of smartphones, are also the latest examples of a shift in smartphone design: Modularity. The concept is simple and attractive: Enhance the performance of the smartphone in your hand by adding or swapping one part of the phone for another.

While the aftermarket accessory market has been filling this need with snap-on camera lenses and various battery-life extenders, the modules that dress Moto Z Force, called Moto Mods, bond with the phone in more esthetically appealing way, as though that’s how the phone came from the factory. Both phones and modules work instantly with each other, so you don't have to mess with installation guides or make settings adjustments.

Motorola made the module-swapping part a lot easier than the system on the LG G5, the other modular smartphone in our Ratings. On the G5, module changes often require some rocking, tugging, and the extra hassle of transferring the phone’s main battery to each new module. With the Moto Zs, the Moto Mods easily attach and detach to the back of the phone using magnets. The magnets are powerful enough to keep the modules in place with normal handling, but not so powerful that it's hard to pry modules off when it's time for a change.

The “plain” Moto Z, which starts at $624, measures 6 inches x 3 inches x 0.2 (without the decorative back cover) and has a 5.5-inch quad HD display, a 13-megapixel rear camera, a fingerprint reader, a USB Type-C port, and a 2,600 mAh battery. The Moto Z Force, which starts at $720, adds the toughness of a ShatterShield display, which Motorola covers under warranty (just for cracks, not scratches) for up to 4 years from the date of purchase. It also adds a higher-resolution, 21-megapixel main camera with optical image stabilization, and a high-capacity 3,500 mAh battery that Motorola says will provide 40 hours of battery life. (We'll see about that in the lab.) This Moto supports rapid charging, cutting charging time to a little more than 2 hours. Dimensions are the same, except the Force is notably thicker (0.4 inches) and heavier (6.9 oz.).

One thing neither Moto has: a 3.5mm headphone jack. But the phones do come with an adapter that lets you plug a standard headset into its USB Type-C port. Eventually, many wired headphones will be designed to plug into USB Type-C connectors. Of course, you can also use Bluetooth headsets, which are gaining in popularity.

The cable USB Type-C charger is actually part of the charger, so you'll have to buy a separate USB Type-C cable to connect the phone to a computer, for either charging or file transfers. 

Currently, there are three Moto Mods: A battery booster, a speaker system, and a pico projector. We bought the pico projector, called the Insta-Share, with the Moto Z Force we're now testing in our labs. Both the speaker system and the pico projector come with their own batteries to minimize or delay the drain on the smartphone’s battery, and all have a hole to avoid blocking the Moto Z’s 23-megapixel camera. Here are more details on the Moto Z Force and the modules that feed it. 

The Modules

Battery Boost ($70). Motorola promises this Moto Mod will add up to 22 hours of operating time. The Battery Boost module that supports wireless charging costs $70 for the plain black or white version or $90 for those with fancier striped or metallic finishes. You can also get a Battery Boost that offers the same storage capacity, but without wireless charging for $10 less. While it remains to be seen how much these modules will increase battery life, they’ll certainly make your phone heavier. The regular and wireless Battery Boosts weigh 2.6 oz. and 3 oz., respectively.

JBL SoundBoost ($80). This amplified (3W to 6W) stereo speaker comes with a kickstand to prop up the phone when you’re “kickin’ it,” and battery, which Motorola says will add 10 hours of battery life. Keep in mind that this module by itself weighs as much as the phone (5oz). We have this unit on order.

Insta-Share Projector ($300). This WVGA (480p) projector is a nifty way to project whatever’s on the phone screen on a light-colored or reflective surface at up to 70 inches wide. We side-loaded an SD copy of “Dead Pool” and beamed it onto one of the walls in a moderately dark lab. This relatively dark film looked impressively sharp and surprisingly bright, especially when we fine-tuned the image with the Insta-Share’s focus wheel.

The center of this hump-shaped Moto Mod has a flap-like stand that allows you to angle the projector upwards to avoid obstacles. Note: The projector shows exactly what’s on the phone’s screen, so you need to check before you project the image. For instance, you'll want full-screen landscape mode for movies, slideshows, and work-related presentations. Just be careful when handling the projector when it’s on. The projector light is blindingly bright. I looked at it for just a second, and I was seeing spots for at least 20 minutes.  

The Phone

The Moto Z Force, which functions just fine without the modules, is well equipped but otherwise unremarkable. In addition to the features mentioned above, it comes with a Snapdragon 820 quad-core processor, 4GB of RAM, and a “water repellent nano-coating,” which means don’t panic if you accidentally spill your bottle of Aquafina water in it, but move like lightning if it falls into the toilet.

It’s a Whopper. At 6.9 oz. this is easily one of the heaviest phones you’ll ever hold. And you’ll notice its heft even more when it’s parked in a shirt pocket.

Battery charges fast, but . . . Motorola says the quick charger can revive a near-dead battery in 15 minutes to provide 15 hours of power. That seemed to be true in my informal use of the phone. However, the phone did seem to drain rather rapidly, at least according to the phone’s own battery gauge. After about an hour of light activity (some email, web streaming and social network activity), the battery gauge reading slid from 100 percent to 80 percent. That seemed a little too fast for a battery that claims 40 hours of life. We’ll have to wait to see the results of our more precise lab tests.

Things fall apart. Since I was playing with the model we’re actually testing, and it had many tests ahead of it, I didn’t want to risk breaking the phone by tossing it over the second-floor balcony at Consumer Reports headquarters (as I did with another tough Moto a back in October). But I did drop it several times on the carpeted floor of my office, and each time the Moto Mod cover popped off. Not a big deal, but a little unnerving nonetheless for a phone that claims to be resilient.