Hardware that I used: Wade's Hobbed Bolt - 60mm, groove is center, 30mm. Prusa Extruder Springs from Ulimachine. https://ultimachine.com/content/prusa-extruder-springs Guidler: 2 version, one for 1.75 filaments, it uses M3x40 mm bolt and the other for 3mm filaments and it uses M3x50 mm bolt. Optional Step: I filed down the M8x20 mm grub to get the 608z ball bearing on the guildler as close to the hobbed bolt as possible, especially when printing 1.75mm flexible filaments. See pic. Jhead Clamp: 2 - M3x30mm bolts, washers and nuts. Jhead Shroud: Used 1 - M3x15mm bolt & nut to attach shroud to extruder body and 4 - M3x20mm bolts & nuts to attach 40mm fan & i3 cover to shroud. Note: The way it's design, you'll need to attach shroud first before attaching the fan. I'm thinking I'll design another shroud but for 30mm fan instead. 50mm Fan Duct: 5 - M3x20mm bolts & nuts Other Instructions: It's pretty straight forward but if you need instructions. Go here: http://reprap.org/wiki/Prusa_i3_Rework_Extruder_assembly