The moderate hardness of the smoother guides the cue, naturally helping you develop the feeling of a straight stroke. This is especially a useful support tool for correcting the tendency to apply unwanted side spin, which is common for those who feel they have a stroke habit that easily causes miscues. Modern high-tech shafts, including carbon fiber shafts, have very high performance, and are designed to pocket the ball easily if you can stroke the cue straight at the intended thickness. However, the action of "simply stroking straight" is more difficult than you might imagine, and it's not uncommon to unintentionally apply side spin without realizing it. For beginners who haven't yet solidified their cueing action, it functions as a guide to help them learn the standard of "stroking straight" without developing unnecessary habits. With a thin design that interferes as little as possible with the bridge-side feel, you can practice the correct stroke path repeatedly without disrupting your usual form or feel. On the other hand, for intermediate players who have begun to recognize their stroke habits, using this allows them to perceive the left-right deviations and grip tension at impact, which are difficult to notice on their own, as objective sensations. You can feel the misalignment of the cue after you address the ball, and it is also possible to correct the misalignment of the cue line during the address. It is suitable for adjusting and confirming your stroke by feeling the "moment of deviation," without excessively restricting movement or forcibly correcting your form. Material: Internal core: PLA resin Inner and outer: Microfiber cloth Dimensions: Length: Approximately 10cm Optimally designed for 11.8~12.5mm pro taper high-tech shafts.