Q: How about the noise level of your motor and do you have quiet motors?
A: Normally we define the noise level (dB) based on the back ground noise and measure distance. There are two kind noises: mechanical noise and electrical noise. For the former, it's related to the speed and motor parts. For the latter, it's mainly related to the sparks caused by the friction between the brushes and commutator. There is no quiet motor (without any noise) and only difference is the dB value.
Q: How much I should pay for samples?
A: For low cost samples with quantity no more than 5pcs, we can provide them for free with freight paid by buyer (if clients can provide their courier account or arrange courier to pick them up from our company, it'll be okay with us). And for others, we'll charge sample cost and freight. It's not our aim to earn money by charging samples.
If it matters, we can make a refund once got the initial order.