Hitachi NR 90AD Technical Data And Service Manual page 13

Head Guard [2]
Head Valve [9]
Exhaust Valve
Rubber [11]
Accumulator
Piston [13]
(Driver blade)
Cylinder [15]
Body Ass'y [24]
Piston Bumper [31]
Nose [29]
Pushing Lever (A) [35]
Plunger Spring [68]
Switching device
(Change Knob (C) [46])
Exhaust Cover [5]
Control valve section
Control valve section
Valve Piston [66]
Valve Bushing (B) [63]
Valve Bushing (A) [71]
Plunger [70]
Fig. 3 Construction
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Cap [41]
Trigger (C) [50]