i read on a magazine that there are actually B18C1 2 3 4 5.... depending on the number after the C, it basically tells where the motor was made... i cant really recall the article i read but i think like the B18C5 is actaully made in Austrialia or soemthing, i dunno i cant remember the exact locations on where the motors where made but the nubmer just basically tell where it was made from...i could be wrong so...yeah....