This is a 13x4E Electric ONLY Composite Propeller from Advanced Precision Composites.
Gray composite one-piece construction
Five adapter rings that adapt to different motor shafts
One composite propeller
Five composite adapter rings for motor shaft diameters of 0.128" (3.2mm), 0.158" (4mm), 0.197" (5mm), 0.237" (6mm), 0.313" (7.9mm)
ALL props require balancing, this is very important, use a Top flite power point propeller balancer
May need prop reamer, use great planes precision prop reamer standard or great planes precision prop reamer metric
Hub inner diameter: 0.25" (6.3mm)
For use with Electric motors only. Do not use with nitro or gasoline powered engines.