Hey Brian,
I have had a WOT on my Excal for almost two years and haven't put another coil on since. To answer your question, the WOT is a 15" coil made by Coiltec company out of Australia. They call it WOT, which stands for Wonderful Orange Thing. The link I put at the bottom will take you to Doc's web site, he's a forum sponsor and a really nice guy.
On his site, he also has instructions on two way to connect the coil, either with a waterproof connector so that you can switch coils, or instructions on how to hard wire it right into the control housing. The instructions also come when you buy the coil.
As for performance, like I said earlier, I haven't used another coil for two years. The 15" WOT gives you lots of coverage when sweeping back and forth, it does go deep, and it picks up the small stuff.
Good luck,
-Rich
Here's a pic of some of the good stuff I found using the WOT: