The Yonex Muscle Power 5 (MP5) badminton racket has steel shaft and isometric design aluminum head/frame based on Yonex's Isometric head shape technology to provide 32% larger sweet-spot than conventional badminton racket.
In year 1992, YONEX developed the world's first epoch-making technology in badminton ...the "ISOMETRIC Square Head Shape". This YONEX development continues to sets the pace of winning play. The Isometric Square Head Shape badminton racquet design provides a 32 percent larger effective hitting area than a conventional badminton racquet. Also, unlike a conventional badminton racquet with main and cross strings of varying length, the Isometric Square Head Shape equalizes the length of main cross strings in the stringbed-enlarging the sweetspot all-around for more consistent shot accuracy even on off-centre hits.