those are only for RVs and Mobile homes. You cannot use them in a regular building.
I didn't mean to mislead; I really don't know. The consensus on Electrician Talk and Mike Holt seems to be to not use them (with most saying they don't meet code, but some arguing they do). The instructions mention the code sections they comply with. Among the sections dealing with mobile homes (550 or so I think), they mention 334-40(B):
334.40(B) Devices of Insulating Material.
Switch, outlet, and tap devices of insulating material shall be permitted to be used without boxes in exposed cable wiring and for rewiring in existing buildings where the cable is concealed and fished. Openings in such devices shall form a close fit around the outer covering of the cable, and the device shall fully enclose the part of the cable from which any part of the covering has been removed. Where connections to conductors are by binding-screw terminals, there shall be available as many terminals as conductors
Maybe that is a mis-application, but I did see some references to it by those arguing that they were allowed for remodels. That's what I was basing my recommendation on to check them out with the AHJ. I'm not an electrician, nor do I play one on TV.
Edit: Meant to include a sample link representative of the debate (controversy?) surrounding these:
http://forums.mikeholt.com/archive/index.php/t-92003.html