Extra mass is easily added on the rear (see picture above). Either one, two or all three included mass loads can be added, or any custom mass object can be added simply using an M8 nut for fastening. The loads included with PR178WA01 do not require any nuts as they are made with M8 threaded center holes.
For experiments trying out different values of moving mass for different tunings, it is usually sufficient just to tighten the loads/nut by hand.
Once the final mass has been determined it is recommend to add some adhesive to secure the loads from coming loose during operation.