4x 608z bearings http://www.dx.com/p/rapid-prototyping-bearings-for-3d-printer-silver-309048?Utm_rid=48516041&Utm_source=affiliate
4x M6x25 mm machine screws
4x M6 nylon insert locking nuts
3D Printer
Some filament
Hint: You print 2 of these. And 4 pins if you don't use nuts and bolts.