This is a frame that accepts Hubsan X4 micro quadcopter guts. Motor openings may need to be manually enlarged based on printer settings. All models should be complete solids now. Versions are in order of apperence above. These frames are designed to fit 7mm motors, however with a little heat and the right tools 8mm can fit. V3: I took everything i did on the V2.1 frame but did it right this time. Box now fits the Flight control board/ receiver. Added bigger gusseting to the motor mounts after breaking all my V2.1 frames in the same spot. Slimmed down bracing inside the arms and removed excess material to hopefully make this thing within 5 grams of original frame weight but indestructible. V2.1 Even more gusseting, more speed holes, better "engineering". The box in which the receiver board is supposed to mount into was modeled too small! The board will not fit into the box as it was designed to do. This frame was 12grams printed .2mm, 4shells 0%infill PLA V2. Redesign with same idea in mind, lighter yet. defiantly have to play with printer settings to make this one strong. * This design is flawed, see above!** V1.1 Slimmed down the arms a bit and added gussets. little lighter. V1. Super strong but super heavy.