G This is a 4.1x4.1 Speed 400 Electric Propeller from Advanced Precision Composites. For use on Electric powered aircraft only, not for glow powered engines. FEATURES: Constructed of Gray composite material For Speed 400 motor applications Two adapter rings that adapt to different motor shafts INCLUDES: 4.1x4.1 Speed 400 Electric Propeller, two adapter rings and instruction sheet REQUIRES: Assembly onto motor shaft or gear drive unit in Electric plane SPECS: Diameter: 4.1" Pitch: 4.1 Hub inner diameter: (8mm) where rings are installed Inner Diameter of Rings: 3/16" (4.9mm) and 1/4" (6mm) APCPart APCLP04141E