There are two generators associated with the KidWind Wind Energy Kits.

Both the Basic Wind Energy Kit and the Advanced Wind Energy Kit come with the KidWind Wind Turbine Generator with Wires (KW-GEN). The Wind Energy Generator has a diameter of about 3.2 cm and a length of about 3.4 cm (including the shaft). The shaft is 2 mm in diameter. This generator is also the one installed in the nacelle of the KidWind Mini Wind Turbine.

Wind Energy Generator Specifications:
Rated Voltage: DC 5.9 V
Rated Load: 10.0 g-cm
At no load:
     Speed = 2000 RPM
     Current = 0.011 A
At stall:
     Torque = 40 g-cm
     Current = 0.147 A
At maximum efficiency:
     Efficiency = 60.851%
     Speed = 1569 RPM
     Torque = 8.6 g-cm
     Current = 0.040 A
     Power = 0.144 W
At maximum output:
     Speed = 999 RPM
     Torque = 20 g-cm
     Current = 0.079 A
     Power = 0.214 W

The Advanced Wind Energy Kit also includes the High Torque Generator with Wires (KW-HIGEN). This generator also has a 2 mm diameter shaft, but the body has a diameter of about 2.4 cm and the total length is about 4.3 cm (including the shaft).

High Torque Generator Specifications:
Rated Voltage: DC 12.0 V
Rated Load: 45 g-cm
At no load:
     Speed = 12800 RPM
     Current = 0.13 A
At stall:
     Torque = 320 g-cm
     Current = 4.183 A
At maximum efficiency:
     Efficiency = 63.098%
     Speed = 10879 RPM
     Torque = 48 g-cm
     Current = 0.738 A
     Power = 5.588 W
At maximum output:
     Speed = 6400 RPM
     Torque = 160 g-cm
     Current = 2.156 A
     Power = 10.956 W

Download the full specifications:
http://www2.vernier.com/til/3155/3155-wind_turbine_and_hi_torque_generator_specs.pdf

See also:
Which generator should I use to pump water?
KidWind Wind Turbine Generator with Wires (KW-GEN)
High Torque Generator with Wires (KW-HIGEN)
KidWind Basic Wind Experiment Kit (KW-BWX)
KidWind Basic Wind Experiment Kit (KW-BWXC)
KidWind Advanced Wind Experiment Kit (KW-AWX)
KidWind Advanced Wind Experiment Kit (KW-AWXC)