Features1Prime Materials: This electric bicycle mid motor crank arm is made of aluminum alloy, durable and strong support. 2Small and Lightweight: This crank arm is designed to be small and lightweight, so it won't put too much pressure on the electric bikes. 3Easy to Install: This mid motor crank arm is easy to install and disassemble, practical, simple to operate and easy to use. 4Sturdy and Non Deforming: These crank arms are sturdy and durable. High strength, high hardness, not easy to deform. 5 Accessories: This motor crank arm is ly suitable for BOSCH mid motor, bringing good experience and performance performance.SpecificationItem Type: Mid Motor Crank ArmProduct Material: Aluminum AlloyWeight: 540g / 19.05ozCenter Distance: Approx. 17cm / 6.69inSpecification: BNI MINI ISIS spline hole (10 teeth, raised point inner diameter about 15mm)Package List2 x Crank Arm