The review for the Head Ti-S5 CZ Tennis Racquet is the same for the Ti-S5. The ComfortZone Technology made a big improvement Ti.S4 CZ, by increasing the stability of the racquet on off center hits. However the original Ti-S5 is very solid even without the ComfortZone Technology. What will the CZ add to the Ti.S5 to make it better? If you're looking for a little more pop on the ball, CZ will add a little acceleration to your shots. The CZ will reduce the string vibration and make your racquet play very quite and smooth. It feels as though the entire face is a sweet spot (very similar to the Volkl V1). The Head Ti-S5 CZ tennis racquet is very close to the same racquet except with more control and a little less power. America's #2 seller, Head has designed a racquet that seems to have all the answers for the club player with medium to full swing. You get the maneuverability you expect out of light weight racquet, solid with comfort on all shots, even on off-center hits, something you don't expect from a lighter racquet. The entire face feels like a sweet spot. The fan string pattern pushes the sweet spot out towards the head helping with groundstrokes and serves that are hit in this area. The Comfort Zone technology is a patented dampening system made up of a combination of a hard and soft material reduces string vibration up to 25%. The cone shape grommets provides for ultimate comfort. The sweet spot is enlarged by 20% and ball acceleration is increased. The Ti-S5 CZ measures 27 3/4" long. This well designed racquet gives you the advantage you expect out of a longer racquet, but plays with the maneuverability and comfort of a standard length frame. This racquet has an emphasis on an even combination of power and control. Shots are crisp, off center hits still pack a punch. You really notice the stability on the top of the racquet when serving! One of the things we especially like about the this racquet is the ease of hitting flat or spin groundstrokes. A nice comfort feel on shots with topspin or underspin.