Gamma Jet String Review

Control - Score: 86 / Power - Score: 40

Made from a stiff, high-molecular-weight material, Gamma Jet doesn't stretch like a multifilament or natural gut string. This gives it a firm and controlled response, which allowed Chris to attack the ball with impunity. He explained, "I'm a big fan of firmer, more control-oriented polys. It was obvious that Jet is a control string from the first hit. I found the response to be crisp, firm and low-powered — much like a traditional poly. I string at a somewhat low 48 lbs, and it felt like I got some power back from the lower tension. Still, the string felt firm, with tons of control. I really enjoyed how I could attack the ball aggressively without worrying about overhitting. When moving inside the court, I could really go after my approach shots. The same rang true on passing shots, and I felt comfortable flirting with the lines and adding some additional pace. During the test Jet became my go-to choice for fast-paced matches. Jet was the most controlled of the four co-poly strings I was testing at the time."

Like Chris, Michelle was also impressed by Jet's control, especially early in the playtest. She explained, "I found this to be a firm, control-oriented string, which is perfect for my game. I liked how it felt right off the stringer when I installed it at my usual high tension. I was satisfied with the control throughout the playtest, but I did experience a slight loss of playability and feel over time. That said, Jet has everything I'm looking for in a string, namely built-in control and spin to help with the weaker areas of my game. I could confidently take big cuts at the ball because I wasn't worried about overhitting."

Spin - Score: 88

Although Jet isn't the best spin string we've tested, its construction reads like the dictionary definition of a spin string. For starters, it's a stiff monofilament made from firm polyester, giving it the low-powered response required for maximum stroke speed. Secondly, it's shaped, which gives it the ability to grab hold of the ball. Finally, Jet's low-friction surface allows the main strings to deflect further at contact so they can snap back with greater force and load the ball with rotational energy. Putting it more directly, Michelle said, "The spin potential seemed awesome here. It felt like a pretty grippy string. My flatter groundstrokes appreciate any extra free RPMs I can get with a shaped string, and Jet provided. It allowed me to pick up the spin and tap into the defensive side of my game when needed. Angles and high defensive shots were enhanced with this string's shape."

"The level of spin I got from Jet was solid," said Chris. "I didn't get the ultra-grippy, spin-loaded response I get from the leading spin strings, but Jet was far from lacking. I found ample spin to roll angles, get lobs to drop inside the lines and go after shots without fear of the ball sailing. Combined with the control-oriented response, I found that the solid level of spin makes Jet a good choice for aggressive hitting. I was also able to get ample spin for the ball to drop quickly on softer touch shots."

Comfort - Score: 65

If you're looking for the plush and pillowy response of a multifilament or natural gut, Gamma Jet has no business being in your shopping cart. It may not be the stiffest string we've playtested, but Jet is definitely on the firm side of the spectrum. For Chris, getting the tension right was key. He said, "Jet offered a firmer feel than many newer co-polys, but it still felt softer than a traditional poly string. I found the string adequately comfortable. I liked it a lot at 48 lbs; dropping the tension a little seems like a good way to get the stringbed to pocket the ball more."

Like Chris, Michelle had no problems with Jet's firmer feel, but she too had some tension advice. "I had no discomfort with Jet strung at the high end of the tension range, but this is a firmer, stiffer string — not soft by any means. Players who prefer softer co-polys should probably drop the tension several pounds."

Feel - Score: 75

In the Tennis University String Lab, Jet's stiffness value was virtually identical to that of Volkl Cyclone, a staff favorite. This helps explain why our team gave it such high praise for feel. Needless to say, Michelle was impressed. She said, "This string felt firm and low-powered — in a good way! Again, after a week or two of use, I lost a bit of tension and felt less connected to the string. It never felt too springy, though, so I always had enough control to hit my targets."

For Chris, Jet checked all the right boxes in the feel department. He explained, "The feel and response from Jet was crisp and firm. I felt pretty connected to my shots. I use poly-based strings because I enjoy a slightly deader, firmer feel, and Jet definitely met my needs."

Playability Duration - Score: 70

Like virtually every polyester we've playtested, Jet loses tension over time. This kind of tension loss invariably results in changes to the feel and control. For Chris, these changes didn't cause any serious issues. He explained, "I had two to three weeks of decent playability from Jet before I wanted to install a fresh set. Like all poly-based strings, Jet lost tension. However, I found this to be a low-powered string, so even when the tension dropped, the power level stayed relatively consistent and the control remained."

"With the usual tension loss that happens with polyester strings, I didn't feel as connected to the ball after a week," said Michelle. "It wasn't horrible, but it was noticeable. I probably wouldn't want to keep the strings in for longer than two weeks or so."

Overall - Score: 80