Feature: 1. 104mm BCD. 2. 170mm length for crank arm. 3. Square tapered crank arms. 4. Compatible with 8 / 9 / 10 / 11 speed. 5. Aluminum alloy material for light weight and strong strength. 6. Suitable for most mountain bikes. 7. Come with a 4-bolt chainring.Narrow\u0026wide teeth increase chain retention and wear life,reduce friction and noise. Specification: Good replacement for your mountain bikes. Features： 104mm BCD. 170mm length for crank arm. Squre tapered crank arms. Compatible with 8 / 9 / 10 / 11 speed. Aluminum alloy material for light weight and strong strength. Suitable for most mountain bikes. Come with a 4-bolt chainring.Narrow&wide teeth increase chain retention and wear life,reduce friction and noise. Specification: Model: 2pcs Crank Arms / 2pcs Crank Arms& 1pc Chainring (optional) Color: Black / Red (optional) Chainring Teeth: 34T / 36T (optional) Crank Arm: Material: Aluminum alloy Compatible: 8/9/10/11 speed Fits pedal size: 9/16" BCD: 104mm Length: 170mm Weight: approx. 510 g / 18.0 oz (for a pair) Chainring: Chainring Teeth: 34T / 36T (optional) Diameter: 144mm / 153mm Material: Aluminum alloy BCD: 104mm Fits chain size: Standard 1/2" X 1/8" Package List: 1* Right Crank 1* Left Crank Arm 4* Pair of Bolt 1* Chainring Package List: 1* Right Crank 1* Left Crank Arm 4* Pair of Bolt 1* Chainring