Works on 3 to 12 volts,slow out put great for radar scale rotation depending on voltage applied.
Shaft apears to be 2.3 mm with a flat.Shaft is center of gear box.
High quality smooth operation and high torque.
I have several and even smaller ones with longer shafts.
Measures 6.1 mm by 20.0 cm
Made by Cannon Seiki
35.00$ each plus shipping