Only fits 145 mm motors. This is the distance between the bolt holes opposite each other across the center of the motor.
If your motor only has a single bolt pattern, this will not fit. If your motor has 2 bolt patterns, this basket will fit.
Cast aluminum HDX series baskets are compatible with HDX3 or HDX4 series subwoofer recone parts. This basket will also fit most HDC series motors in the case of an upgrade using an HDX3 or HDX4 recone kit.