The clamping screw aperture: 3mm
The axial screw aperture: 4mm
The axial installation diameter: 3mm/4mm/5mm/6mm/7mm
The edge to edge size: 12mm
The total length: 18mm
Note:The 7.4v 2600mah will change package,so the battery will be delivery in red or purple.Description:Basic information Model:144001Speed:60km/HPower..