The FTC Drive Base Kit v2 (70400-v2) is an upgrade from our first version (part # 70400). It includes our new slim mecanum wheels with bearings on all rollers, allowing you to make a wider base robot. It also has 4 NeveRest Orbital 20 Gearmotors with encoder cables, the new Clamping Shaft Hubs, 4 bumpers and complete hardware to complete the chassis.