The new subwoofers ST12-D2 and ST15-D2 starting from the basket are designed exclusively for SPL competitions. In order to obtain the best performance on each race circuit, we have used the best materials and all our experience, to achieve maximum efficiency and power handling, obtaining the maximum SPL in every competition. In order to guarantee a constant and uniform flow, it is equipped with high magnetic permeability plates. The oversized magnet provides perfect control even in very high hiking conditions. Basket and motor are coupled and damped through a special epoxy glue.