MK8 drive gear for direct drive exstruder for 5 mm shaft, effective diameter 7 mm, OD 8mm and height 11mm. MK8 is a new evolution of the MK7 Drive Gear. The smaller diameter gives 35% more power. Made in stainless steel and are good for 1.75 filament. If you need a replacement gear for Makerbot Replicator or you’re designing your own custom project, this is the part!