Complex sentence: The three sizes of a tee are end x end x center, so a tee that is 1 on both ends and 3/4 "in the center it would be 1" x 1 "x 3/4".
Split into simpler sentences: The three sizes of a tee are end x end x center. So if you want a tee that is 1 on both ends and 3/4 "in the center it would be 1" x 1 "x 3/4".