This is a 13x4E electric only composite propeller from Advanced Precision Composites.
Includes: Composite propeller and 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)
Requires: Props require balancing and may need prop reamer
Hub inner diameter: 0.25" (6.3mm)
Note: For use with electric motors only. Do not use with nitro or gasoline powered engines.