Yonex Muscle Power 1 Badminton Racquet - Lime/Strung Flex: Stiff Frame: Aluminium Shaft: Steel Weight/Grip Size: 2U (90-95g)/ G4 Stringing Advice: Pre strung with Yonex String @ 23-24lbs Colour: Lime Bag: Comes with Yonex head cover Made in China The Yonex Muscle Power 1 (MP1) badminton racquet is similar to the Yonex Isometric 22 badminton racquet has steel shaft and isometric design aluminium head based on Yonex's Isometric head shape technology to provide 32% larger sweet-spot than conventional badminton racquet.Muscle Power is Yonex's futuristic design of rounding corners to help realise the frame's full power potential. Instead of seating the string on the sharp points of a traditional grommet hole system, Muscle Power seats the string on Round Archways that cause no string stress-load and no fatigue through contact friction. The construction creates total unity of the frame and string because they are in much closer and tighter contact. The face stability that results from rounding the corners lets you smash with a new magnitude of aggression.