It has 4 on board inputs and has an expandable dock which allows you to connect multiple timers so that they essentially function as one time base, with more than 4 inputs. There are a few versions of the dock that seem to be available.
I will have one in hand in a little over a week, I would have had it sooner, but I was away and had no use for it.
http://www.tagheuer-timing.com/_imgtiming/Specifications/en/CP540.pdfJenna