factory tach question

I'm the guy that bought the tach on eBay for $237.50. I was very happy to get it for that price. It just arrived today and I don't know if it works. Does anybody on this thread know if this tach needs a sending unit?

I actually wanted a 1967 tach, but I haven't seen one and none of the repos look very good. I think the original tachometers look very cool. $200 is a good price.