Shimano crank 105  (53/39T-172MM) Double 
Lightweight HollowTech II 105 10-speed chainring kit. Lightweight SG-X aluminum chains are anodized for smooth, precise transmission. For use with the ST-5700, ST-6700, or ST-7900.
Innovative HollowTech forged aluminum crank arms use a hollow design that reduces flex and keeps weight low
The chain teeth have been developed to work in conjunction with CN-5701 chains for increased contact to provide greater efficiency and improved power transmission.
HollowTech II allows the bottom bracket bearings to be spaced more widely (outside the frame), enabling the use of larger bearings and a larger pivot diameter
The system allows for easy installation, modification and maintenance.