why the weight unit of badminton racquet is 'U' but no others? what U stands for? why the weight unit of badminton racquet is "U",what U stands for? There is a history both in material and in weight about that, known to all, using carbon graphite to make badminton racquet is one milestone in about 1969s,and the other milestone is in the weight,that successfully lighten the weight of badminton racquet to 100gram,before that,tempo of game is so slow for the racquet is heavy(about 130gram or more),for the technological skill improved,racquet weight can be controled to 100gram,whice is the other milestone. U stands for "Under 100gram",how many U stands for how many gram under 100gram.1U =5gram,(people can feel difference obviously 5gram weight increment or unweight) so 3U is 3*5gram=15grams less than 100gram, that is why 3U=85g-89g.