Hi there I used graupner motors for years they are a great motor but as some tattooists use low amp power supplies it will not run the motor and erly eikon ps blow up .. So I say think on them they need at least 3+ amps on a ps to run them .. I loved using them but I no longer use them I it's the Mfa motors good price and solid motors but again much bigger the the Maxon motor .. And Mfa are low amp 0.35 amp where graupner are 4. Amp .. And the graupner are 19000 rpm Mfa are 13000 rpm .. Hope this helps .... Dale