Type (optional): 550-12V-8000rpm, 550-12V-10000rpm, 550-12V-12000rpm, 550-12V-15000rpm, 550-12V-18000rpm, 550-12V-23000rpm, 550-12V -30000rpm, 550-12V -40000rpm, 550-6V-8000rpm, 550-6V-10000rpm, 550-6V-14000rpm, 550-6V-18000rpm, 550-6V-20000rpm, RS390-12V- 20000 revolution, RS390-6V-18000 revolution.
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