Mike owns more than two hundred pairs of athletic shoes, many of which are brand new.
The statement you provided describes the ownership of athletic shoes by an individual named Mike.
"Mike owns more than two hundred pairs of athletic shoes": This part indicates that Mike possesses a collection of athletic shoes, and the quantity is greater than 200 pairs.
"Many of which are brand new": This additional information suggests that a significant portion of Mike's athletic shoe collection consists of items that are in a brand-new condition.
In summary, the statement conveys that Mike has a substantial collection of athletic shoes, exceeding 200 pairs, and a noteworthy portion of these shoes are still in brand-new condition.