I bought one for my civic vx that installs in a threaded plug in the front of the block, not the drain plug, but I can't get that plug out! I think I paid about $35 for mine from the dealer, the one you have looks to be $42 +$2 for the wire harness.
http://www.hondaautomotiveparts.com/...S+-+ELECTRICAL
it's part #40 and #40a
Mine looks like a tiny water heater element and looks really solid and well built, tempted to take it to a repair shop to have it installed.