Designed to all-metal j-head hotend (from aliexpress like this one: http://www.aliexpress.com/item/0-4mm-0-3-0-5-Nozzle-E3D-All-metal-J-head-Hotend-Full-Set-with/32307131474.html?spm=2114.32010308.4.37.LTJMoM) Updated: Param to configure relative difference of hotend heights //Relative difference from right to left hotend (max 5mm) relative_difference = 0.0;