A Z-axis top bracket for your prusa i3 Hephestos if you wish change the original 5mm threaded rod for a 8mm threaded rod or lead screw, up to you !
[EDIT 03/12/2017] I removed the bearings and it resulted into better prints, don't use this thing ;)
The bearing is a KP08, you need to dismount it form its original bracket by twisting it out, then hammer it in this part.
Once this is done, GENTLY hammer your 8mm smooth rod in, and you're done !
This is a remix from Oneira3D's thing n°516294 and cmd's thing n°799588