Based off Cellstruder v1, http://www.thingiverse.com/thing:109040, except it has the ability to retract the syringe. Therefore, it has an enclosed design with a lead nut for retraction on the lead screw. It also has a switched up lm8uu holder to add a better grip over the linear bearing. Last, included is a syringe holder for a standard printed x-carrage. Enjoy!