I use and recommend the TASCO Circuit Mapper System CMT42S.
http://www.tasco-usa.com/CMT24S.htmIt works as advertised.
It permits you to hook up all #14, #12, #10 conductors via inductive pick-ups AT THE SAME TIME.
You then can digitally wand the receptacles without disconnecting the power.
It's only weakness is that doing all of that wipes out the 9VDC battery rather quickly, so you must have fresh spares.
It's a huge time saver and most impressive to my patrons.
