If you have a "steep" or very thin seat post (width of 5mm at attachment point), while the universal attachment clip will work, you may prefer to insert the shim. The shim is made from a semi-rigid urethane plastic that will flex and conform to your seat post. This makes for a "custom fit" of your Smartmount. Comes with a cable tie. NOTE: When purchasing any of our race number holders, you can choose the option to add the shim at no additional cost.
All prices are in USD.