New trigger, VERY slightly taller than stock, larger, square pad. Needle cap holder ("needle cap dock") on end of pre-set stop at end of handpiece. New needle chucking guide with auxiliary lever attached (al la Eclipse, HP Plus lines). The first two (trigger and handpiece with needle cap dock on preset) are compatible with earlier Micron models and other Iwatas like HP series. The chucking guide, so I'm told, is not.