This is the Parc Drive 300+ 4:1 Ratio Gear Drive System from Simprop.

      Designed for use with the Park Flyer airplanes or other models that
          require a speed 280 motor and a 4:1 gear ratio gearbox.

FEATURES: Light weight, easy to use power system for park flyers.
          Pre-assembled nylon gear box with bushings.
          Bushing motor

INCLUDES: One Power Speed 280 ferrite motor
          One Parc Drive 300+ 4:1 ratio black gear box with 8mm output shaft
          One 11 tooth pinion gear
          One 8mm black nylon prop nut
          One APC 10x4.7 slo-fly propeller (APCQ5015)
          Three motor capacitors
          Two 2 x 6.5mm gearbox mounting screws
          One instruction sheet (written in German)

REQUIRES: Park Flyer aircraft
          Electronic speed control
          Fine-point felt-tip pen for marking motor placement in the gearbox.
          Small phillips screwdriver

COMMENTS: Electric flight facts:
          Higher gear ratio: Propeller spins faster, but has less power.
          Lower gear ratio:  Propeller spins slower, but has more power and
            allows the use of a larger propeller.
          Smaller propeller: The airplane will go faster, but has less power.
          Larger propeller:  The airplane will go slower, but has more power.
          Larger pinion: The airplane will have more speed, but will not climb
            as well.
          Smaller pinion: The airplane will have more power, which is used for
            aerobatics.
          Ball bearings give better performance and run smoother than bushings.

          Drive units from Simprop are listed here from "basic" up to
            "high performance" aerobatic.
            GPMG0251 Econo Drive 300+ 5:1 Ratio (Basic, not aerobatic)
            GPMG0250 Parc Drive 300+ 4:1 Ratio (More powerful, not aerobatic)
            GPMG0253 Power Drive 350+ 5:1 Ratio (More powerful than the 300+
              gear drive because it has a stronger motor. It has more
              aerobatic capabilities.)
            GPMG0252 Acro Drive 350+ 5:1 Ratio (Has ball bearings in the motor)
            GPMG0254 Acro Drive 350+ BB 5:1 Ratio (Has ball bearings in the
              motor and the gearbox.)
                                                                     JAL 1/5/01
                                                                          ir/jl