Chalugadp, I didn't know. Sometimes it doesn't work out. But you can make a very educated guess. And you start with some basic requirements. For me those were 16ohm, high sensitivity, 10", reasonabl price, etc. that narrows your search considerably.
I wasn't so worried about the woofers. I was pretty sure they'd work out. The tweeter was mandatory. This speaker had to use the SEOS 10. The mids however were a Hail Mary. I had no idea if they'd be good. I had never used a celestion product, let alone one without much user info. They ended up fitting the bill nicely, but I was prepared to ditch them and start over. And that happens often, believe me.
The mid is a celestion from PE. It comes in ferrite and neo. It's kind of a one trick pony, and this is it.