We have added yet another option to the BTL and new BL series, the Universal motor option. This option allows you to fit and swap any of the coils in the specific driver series lineup into the motor. Currently all of the motors are machined specifically to maximize each coil choice. But in doing this, it doesnt allow for different coils to be swapped in and out of the same driver as the dimensions are different for each coil. Now, if you want the option to be able to switch coils and impedance, you simply select the "Universal" motor option.