https://alexnld.com/product/10pcs-creality-3d-8-25mm-leveling-spring-for-cr-10s-pro-cr-x-3d-printer-extruder-heated-bed-part/?hilite="M4*40 Nut Screws and Hotbed Spring Kit for Creality CR-10 / Ender-3 / Ender-3 Pro / CR-10S PRO 3D Printer"