• Port Hole Grommet - the string loops over the outside of the racquet.  This makes the string longer which gives more comfort and a larger sweet spot.  Port Hole Grommets are standard on the Graphites.
  
• String Hole Grommet - a more conventional grommet with tubes that extend through the frame.  This makes the string shorter with more constrained movement.  This gives a tighter feel and more control.  String Hole Grommets are standard on the Rebels.

Tip of Prince Graphite with Port Hole Grommets in it
and a separate String Hole Grommet strip

The racquets come from Prince with a standard set of grommets (Port Holes for the Graphite, and String Holes for the Rebels).  If you want to replace with the non-standard set, please email us after purchase.