Motor with 25 mm diameter and 48 mm length, 9,7:1 metal gear, 6 V  operating voltage, 0,55 A to 6,5 A power consumption, 990 RPM speed and 2,8 maximum torque. Pololu 1571

Motor with 25 mm diameter and 48 mm length, 9,7:1 metal gear, 6 V  operating voltage, 0,25 A to 2,4 A power consumption, 590 RPM speed and 1,2 maximum torque. Pololu 1582

Motor with 25 mm diameter and 50 mm length, 20,4:1 metal gear, 6 V operating voltage, 0,55 A to 6,5 A power consumption, 460 RPM speed and 5,5 maximum torque. Pololu 1572

Motor with 25 mm diameter and 50 mm length, 20,4:1 metal gear, 6 V operating voltage, 0,25 A to 2,4 A power consumption, 290 RPM speed and 2,4 maximum torque. Pololu 1583

Motor with 25 mm diameter and 52 mm length, 34:1 metal gear, 6 V operating voltage, 0,25 A to 2,4 A power consumption, 170 RPM speed and 3,5 maximum torque. Pololu 1584

Motor with 25 mm diameter and 52 mm length, 47:1 metal gear, 6 V operating voltage, 0,55 A to 6,5 A power consumption, 200 RPM speed and 8,5 maximum torque. Pololu 1574

Motor with 25 mm diameter and 52 mm length, 74:1 metal gear, 6 V operating voltage, 0,25 A to 2,4 A power consumption, 120 RPM speed and 4,7 maximum torque. Pololu 1585

75:1 Metal Gearmotor 25Dx54L mm HP with 48 CPR Encoder

Motor with 25 mm diameter and 54 mm length, 75:1 metal gear, 6 V operating voltage, 0,25 A to 2,4 A power consumption, 78 RPM speed and 6,8 maximum torque. Pololu 1586

Motor with 25 mm diameter and 54 mm length, 99:1 metal gear, 6 V operating voltage, 0,55 A to 6,5 A power consumption, 97 RPM speed and 15 maximum torque. Pololu 1576

Motor with 25 mm diameter and 56 mm length, 172:1 metal gear, 6 V operating voltage, 0,55 A to 6,5 A power consumption, 56 RPM speed and 25 maximum torque. Pololu 1577

Motor with 25 mm diameter and 56 mm length, 227:1 metal gear, 6 V operating voltage, 0,25 A to 2,4 A power consumption, 25 RPM speed and 16 maximum torque. Pololu 1589