Constructed with premium aluminum alloy, the crank arm is durable and strong. The center distance between two holes is 170mm. Spindle Interface Type: Horizontal Square Taper. Please check if the orientation of your right crank arm is square or diamond. Keep both left and right arms having the same hole. Suitable for road bike, mountain bike, folding bike, fixed gear bicycle, etc. Material: Aluminum alloy. Size: About 21 x 2 x 1cm/8.3 x 0.8 x 0.4inch(L x W x H). Feature color: as show - Material: Aluminum alloy. - Size: About 21 x 2 x 1cm/8.3 x 0.8 x 0.4inch(L x W x H). - Constructed with premium aluminum alloy, the crank arm is durable and strong. - The center distance between two holes is 170mm. - Spindle Interface Type: Horizontal Square Taper. Please check if the orientation of your right crank arm is square or diamond. Keep both left and right arms having the same hole. - Suitable for road bike, mountain bike, folding bike, fixed gear bicycle, etc. Package Including 1 x Allow Low Profile Left Crank Arm Left 170mm Horizontal Square