Here is a review from Midway for a similar model (looks to be the same, but the model number is different). Price here is better. Reviews are very good, looks like the size (for the small one) is the only drawback. I will be purchasing to test it out.
Midway Review
Does anyone have any experience with this ultra-sonic cleaning of interior parts (AR-15 bolt assembly, pistol barrels, buffer springs, etc)?