Good extendable unit.
Your review: I use Emergi-Lite EF18D(ZF) Surface Mount Par36 Round Remote Fixture - 12V 9W 7x4
B246239 and have installed 5 units this way. Works great.
Pros: Very good price point for an extendable unit. I say extendable because with a little extra wiring inside, the battery has enough power so you can add other lights to the unit and save an extra battery and charger.
Cons: None yet.