My brother gave me his E3D Hemera extruder (YAY, Thank you!!), but his Ender 3 mount plate was not compatible with my Ender 5 mount plate. I tried several variations online, and didn't like how much of my Y axis space they reduced, and because they push the weight away from the rail, high speed maneuvers cause minor rotations that can affect the print. This one will require you to drill a couple screw holes through your metal carriage plate, but the benefit in stability and space savings is well worth it, IMHO.