The Step-Down D24V3AHV Buck Voltage Regulator module with adjustable output voltage in the range of 4-25V with a wide input voltage range of 4.5-42V and a maximum output current of 300 mA. Pololu 2102

Rechargeable NiMH Battery Pack: 7.2 V, 900 mAh, 3x2 AAA Cells, JR Connector

Rechargeable NiMH Battery Pack: 7.2 V, 350 mAh, 3x2 2/3-AAA Cells, JR Connector

Solarbotics RM2 (high-power motor for GM2/3/8/9)

Solarbotics GMB28 (GM2/GM8 Gear Motor Bracket, Laser-Cut Steel)

Machine Screw: M3, 25mm Length, Phillips (25-pack)

Machine Hex Nut: #4-40 (25-pack)

Machine Screw: #2-56, 5/16" Length, Phillips (25-pack)

Aluminum Standoff: 3/8" Length, 2-56 Thread, M-F (4-Pack)

Aluminum Standoff: 1/2" Length, 2-56 Thread, M-F (4-Pack)

Aluminum Standoff: 3/4" Length, 2-56 Thread, M-F (4-Pack)

Aluminum Standoff: 1" Length, 2-56 Thread, M-F (4-Pack)