Specification: Material: Stainless Steel Screw Thread: M6 Nozzle Diameter:0.4mm Input Diameter: 1.75mm Total Dimension: 12.5x7mm / 0.5x0.28 inch (L*D) Package Content: 4 x Nozzle NOTE: Small accessories please keep away from children. After replacing the nozzle please recalibrate the distance between nozzle and build plate to ensure the quality of print parts. How to Replace Nozzles? 1: Turn on 3D printer heat the nozzle and heat block to the target temperature (PLA: 180-220 ABS: 240-280). 2: After heat finishing close printer take spanner to hold the heat block. Then use socket screwdriver to screw old nozzle extruder out. Notice: Please don’t touch the old nozzle and heat block to avoid burning. 3: Spanner keep to hold the hear block use the socket screwdriver screw the new nozzle in make sure tight.