The Shimano 105 ST-5703-L is a left-side Dual Control Lever from the 105 series, combining shifting and braking for triple (3×10-speed) road drivetrains on drop bars. It’s designed for road cyclists building or upgrading bikes with Shimano 10-speed components, particularly those using triple chainsets for a wider gear range suited to varied terrain like hills or longer rides.

Compatible with Shimano FD-5703 or FD-6703 front derailleurs, FC-5703 cranksets, RD-5700 rear derailleurs, and 10-speed cassettes. It works with Super SLR brake calipers such as BR-5700 or BR-6700, and older road calipers like BR-R650. Cables route internally under bar tape with adjustable reach shims allow fitting smaller hands by reducing lever span 5-10mm. Cyclists choose it for reliable front shifting across three chainrings via two shift levers (indexed for large/intermediate and intermediate/small), ergonomic hood positioning that improves braking leverage, and lighter shift action from redesigned internals. It’s a solid mid-range option for 10-speed triples, though discontinued—ideal for vintage upgrades or matching existing 5700/6700 groupsets.