We are a professional Amazon store. If you have any questions, you can contact us at any time. We sincerely create a good buying experience for every customer who comes to each store.Is a legally which has been registered. always focus on customer's expectation and demand, to provide the most excellent shopping experience for customers. 4.The four flat ended compression bed springs improve the rigidly and stability of the print bed.5.The lead screw coupler improves the and reliability of your printer Z axis.colour:Photo ColorMaterial:Aluminum alloyPackage Contents:1* aluminum extrusion machine2* hot end silicone sleeve(Random Color)2* (0.4 mm) nozzle for 1.75 mm filament1* pipe4* flat end compression spring2*NEMA 17 step damper2* stepper motor radiator1* screw hookOnly the above package content, other are not included.Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.