The Spin Machine! No speed glue needed! "Tension increase" gives you 2/3 more spin and 50% more speed. 
Xtend HS is the newest rubber utilizing the STS (Spin-Tension-System) technology by Yasaka. STS is well-known for giving 2/3 of the tension energy to spin and 1/3 to speed. Xtend HS has the same characteristics, but has now been re-designed to deliver even greater power. To comply with the ban on speed gluing, Yasaka developed this powerful new tension rubber. STS still works as before, but the top sheet and sponge have been completely re-designed with ground-breaking new technology. It delivers high-power speed with easy handling, just as players would wish. 
Do NOT apply speed glue, as it will destroy the rubber. Xtend HS is not only fast enough without speed glue, but it is also very sensitive because of the new technology.

Brand Yasaka   Type: Smooth   Speed: 84   Spin: 83   Control: 77   Hardness: 35-40   Sponge Thickness: 2.0,Max