So, it's just a square pan attached to the underside of the cooking grate - but not bad for what it is. Less than 20 bucks and you're done. The immediate thing that comes to mind after seeing the video is "Why not just go down to my local Walmart and buy the pan and a couple of stainless screws and do it myself?" (or just grab an old one from my current home stock)
http://www.ebay.com/itm/Groker-Insert-Instantly-turns-your-charcoal-grill-into-a-BBQ-water-smoker-/200949875327?pt=Barbecues_Grills_Smokers&var=&hash=item2ec98bc27f
http://www.ebay.com/itm/Groker-Insert-Instantly-turns-your-charcoal-grill-into-a-BBQ-water-smoker-/200949875327?pt=Barbecues_Grills_Smokers&var=&hash=item2ec98bc27f