Lenmar's PPU1619 was one of the first external battery solutions that turned up on Amazon during our virtual shopping trip. It's incredibly similar, in our opinion, to the older Tekkeon myPower batteries.
The company more recently released its PPU916, which looks remarkably different. It is housed in a brushed aluminum shell, and the form factor is small, compact, and rectangular. Its shape alone is a plus because it easily fits into a briefcase pocket.
Connectivity is straightforward. You only have to deal with a single input and output port. Voltage is manually selected, but is limited to two voltages (16 and 19 V).
Lenmar takes a different approach to charging, like Electrovaya. Instead of using a discrete charger specifically for the PPU916, you use your notebook's charger, along with one of the input tips (right-angled plugs).
The only issue we ran into was a typo in the company's manual. It states that all five LEDs on the unit are used to indicate charge level, and the fifth LED serves two purposes: indicating 80%-100% and also functioning as the charging indicator.
When we actually looked at the unit, it turned out that the fifth LED is not dual-purpose. This means the scale is actually in 25% percent increments, instead of 20%.