The outside part with the fan attachements, LED ring & magnetic stud ball attachements are sourced (with a few modifications ) from Haydn Huntleys "Magnetic Effector with 3 Fans and LED Light Ring for Kossel Plus" found here: https://www.youmagine.com/designs/magnetic-effector-with-3-fans-and-led-light-ring-for-kossel-plusI use the same magnetic ball studs that Haydn sells for a reasonable price, 12 are needed for a complete printer.The ball studs are exactly 39.7 mm apart, to match the distance between the outer holes in OpenBuilds 20mm V-Slot™ Gantry Plate that I'm using as Delta carriage on my verticals.Update 2016-02-22: Moved fan lugs by 60 degrees for better aim at the tip of each hotend. Also, this frees up some space between the effector and the idler belts.