Needle racquet

In badminton, the balance of a racquet can alter the playing style entirely.
Since particularly good racquets are quite light anyway, it takes a small weight adjustment to move the balance towards the head or handle end.
Therefore I propose a racquet with slots in both the handle and in the frame around the head. Into these slots will fit needles of around 2 or 3 Grammes in weight, which are placed there by the user and are fully removable. Since there are going to be large forces exerted on the head, this area would require that the needles be difficult to remove - this is achievable simply by a small sliding clip, covering the needle to prevent its departure.
It may be more at home in sports shops/training classes where it would be rented out - allowing players to discover their preferred balance before committing to any highly priced equipment, as opposed to a racquet intended for general use.