This is a custom design Waterproof servo by Shadow Hobbies, it has a 90 day warrantee its Unique Power displacement allow for 3 torque ranges 6 volts 325 OZ In 7.4 Volts 375 OZ in and 8.4 Volts 425 oz.in. with speeds 0 .11, 0.13, 0.16 Shadow Hobby se