- Prowheel A10BPP(13) crank arms specially designed for children's and youth bicycles - 6061-T6 forged aluminum alloy construction, offering high strength and durability - 30T chainring in alloy or steel, with black finish and double plastic chain guard - 89 mm crank arm length, adapted for young users - Square tapered spindle interface, compatible with most children's and youth bicycles - Easy installation, ideal for crank arm replacement or repair - Includes mounting bolts - Q Factor: 157 mm, I Factor: 132 mm, chain line: 48.5 mm, chainring thickness: 3/32 inches - Provides additional protection to the chainring and prevents damage to the teeth - Robust and safe solution for children's bicycles