(Sanho notes that the MBP-060 is designed for use with only the MacBook Air, MacBooks, and the 13-inch Unibody MacBook Pro.)

Each model sports an attractive, aluminum enclosure with white-plastic trim, making the HyperMac batteries a nice aesthetic match for Apple's Unibody laptop line. I was also impressed by the build quality of the models we received.

Inside each enclosure is a lithium-ion battery offering 60 to 222 Watt-hours of power, depending on the model. At one end of the enclosure is a panel with a charging jack (for charging the battery), a power button (for toggling the battery on and off), an LED power indicator, a four-LED display that indicates the remaining charge (at quarter-charge increments), a USB jack, and a DC-Out jack.

You charge the battery using the included 6.5-ounce AC adapter; charging takes 2.5 to 6 hours, depending on the model. The company says its batteries can retain a full charge for 180 days; I couldn't test this claim in the time frame of my testing.

To use the battery with your laptop, you connect one end of the included MagSafe cable to the HyperMac battery's DC Out jack, and the other end to your MacBook; as long as there's a charge left in the HyperMac battery, your computer thinks it's connected to AC power. (When ordering, you choose whether you want a cable with the low-profile MagSafe connector that ships with the MacBook Air and recent MacBooks, or with the standard MagSafe connector.)