BETAFPV 2pcs Beta75s 75mm Micro Whoop Frame for 8x20mm Motors Tiny Whoop The strut design is very different and actually creates a complete X all they way back to the battery chamber. The struts between the motor mounts and ducts are fragile and break easily. So these upgraded frames stiffen the struts considerably. The struts themselves have a flat cross section which creates more bonding area with the duct.