Identify this speaker

[drunknmunkys]

http://houston.craigslist.org/ele/1266792837.html

The two floor speakers are Polk Monitor 50s
He says the center is a CM1, not a CMC, but I can't find anything called a CM1 which is 1) a center, or 2) looks like that.

 

[drunknmunkys]

Found it. It's a CS1, not CM1, although he was adamant in his email back to me.