With 24-speed transmission and the trigger handle, the thumb shifter is ergonomically designed to make the ride easy and comfortable. With practical function, the thumb shifter makes you can see the speed changes and fine-tune the speed change with your hands. The thumb shifter is made of high quality aluminum alloy and resin materials, which ia durable and long service life. The length of this product is 12.9cm, the width is 6cm and the height is 4cm. The 24-speed transmission is used for mountain bikes. Item Name: M310 Thumb Shifter Material:Resin,Aluminum Alloy Model: SL-M310 Size:12.9cmx6cmx4cm/5.08inx2.36inx1.57in Notes: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Package Includes: 1 X Brake Line 1 X Thumb Shifter (3 Speed Left or 8 Speed Right)