5pcs M20 1V-7.5V micro motor for aeromodelling toy Adult application 3V17500rpm/7.5V42000rpm high speed size: 8*10*15mm Shaft Diameter :1mm, Axial length: 6mm Voltage: 1V-7.5V Speed: 17500rpm ( 3.0V ) / 42000rpm ( 7.5V )