A. Tees are sized by using the run (straight through portion) of the tee first and then the side outlet. The largest size of the run is named first and then the smaller size of the run and then the side outlet size. Example: 3/4" x 1/2" x 1/2". When only two sizes are provided for the Tee description the run size is listed first and then the side outlet. This means the run has the same size on both ends. Example: 3/4" x 1/2". A Tee that is 1/2" x 3/4" is often referred to as a Bull Head Tee because the run is smaller sized than the side outlet. This way of sizing Tees is the same for all Tees in plumbing no matter what material (PVC, copper, ABS, cast-iron, etc.) is being used.