Redrex Assembled MK8 Extruder Hotend for MakerBot Prusa i3 Reprap 3D Printer

NOTE: ?Make sure the maximum temperature is less than 280°C ?Thermistor sensor is risky demaged if it is fasten too tight.And please do not be panic if it is fallen out as arrived ,it is easy to reset. Specification: Default extrusion nozzle:0.4mm ; The material of Print: 1.75mm PLA/ABS/Wood/Flexible The flow rate of Nozzle: about 24cc/h The voltage of heating element: 12V Thermistor: NTC 100K Cartridge heater: 12V,40W The operating voltage of cooling fan: 12V Stepper Motor:NEMA 17 Number of Phase: 2 Step Angle: 1.8 deg. Rate Voltage: 3.3V DC Holding Torque:1.5A Phase Resistance: 2.2ohms±10%?20?? Motor Torque:40Ncm/57.1 oz.in  Phase Inductance: 3.8mH±20%(1KHz)  Net weight: 480g Normal working temperature: 190°-230°C Package List: 1xMK8 Extruder(0.4mm nozzle)