Why do you need to know?
Different classes are 1/8 Nitro, 1/10 Nitro Touring, 1/10 Electric Touring, 1/12 Electric, 1/10 F1 electric.
The most popular classes in Japan are.
1/10th Touring Class has; Sports Class - 21.5, Open Class 17.5, Modified ~ any motor.
1/12th Class has Stock Championship Motor - 21.5 motor and Modified~ any motor.
Here's the link to the motor page.
Pretty sure the batteries are open to any company.